• Hard Disk Sentinel
• Dos 7.1 hard disk,full version
• One disk drive has only one actuator arm. Every plate has 2 surfaces to store data. Throughput: 100MB/s Seek time: 10msec (100 seeks/s)

One disk drive has only one actuator arm.
Every plate has 2 surfaces to store data.
Throughput: 100MB/s
Seek time: 10msec (100 seeks/s)

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• http://www.buildcomputers.net/hard-disk-speed.html What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.
http://www.buildcomputers.net/hard-disk-speed.html

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.
To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out of
reach for end-users.
If you have already read our SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance
5,400 RPM HDD

75 MB/s

65 IOPS
7,200 RPM HDD

100 MB/s

90 IOPS
10,000 RPM HDD

140 MB/s

140 IOPS
From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False
It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading to
overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details, check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

What makes a real impact on hard disk speed (and what doesn't)? Learn the surprising facts today so you can buy a hard disk that is indeed faster.

To understand what affects HDD speed, we'll first have to give you a crash course on how hard disk drives work:
Data inside a hard disk drive are stored on circular disks called platters. Most mainstream hard disk drives will have one to four platters stacked on top of one another.
To read and write data, the hard disk platters are being spun around at dizzying speeds while a motorized arm moves a read/write head to where the data is located.
High RPM Hard Drive Drive = Fast Hard Disk Speed - True
What is RPM? RPM stands for revolutions per minute, and it's used to measure the rotational speeds of hard disk platters. All other things being equal, faster spinning platters will translate to quicker hard disk drives. In fact, the RPM of a hard disk drive
makes the biggest impact on its overall speed.
Consumer hard disk drives operate at 5,400 RPM to 10,000 RPM, with most desktop HDDs spinning at the standard 7,200 RPM. Just for general knowledge, the fastest hard disk drives clock in at a blazing 15,000 RPM, but these are enterprise-level drives out
of reach for end-users.
SSD vs HDD face-off, then you will know that HDD speed is determined by both sequential performance (for large file transfers) and random performance (for running programs and multitasking):

Sequential Performance

Random Performance

5,400 RPM HDD

75 MB/s

65 IOPS

7,200 RPM HDD

100 MB/s

90 IOPS

10,000 RPM HDD

140 MB/s

140 IOPS

From the above figures, we can see the impact that a hard disk drive's RPM makes on its speed. So all other things being equal, higher RPM = faster hard disk speed
Not too long ago, 10,000 RPM drives were the superstars of mainstream storage, embraced by both techies and consumers seeking performance. However, they have fallen from grace in recent years due to the free-fall in solid state drive prices. While SSDs still
cost more than 10,000 RPM HDDs (per GB), their dominating speed advantage more than makes up for it.
Nowadays if you are buying a hard disk drive for general purposes, 7,200 RPM drives tend to give you best bang for your buck since they offer acceptable hard disk performance (and more storage space) at much lower price points compared to 10,000 RPM drives.
High Hard Disk Density = Fast Hard Disk Speed - True
Most people won't ever bother with hard disk data density (or the number of hard disk platters) when shopping for a new drive, but you should... since it has a real-world effect on HDD speed.
In a nutshell, a hard disk drive with higher data density is able to store more data per platter. Since the data are packed closer together, the read/write head has to travel shorter distances to access data on the hard disk drive. This time saved will translate
to quicker hard disk drive speeds.
Let's say that we have two 500 GB hard disk drives. The two drives are identical, except that the first HDD has one platter, while the second HDD has two platters. In this case, not only is first HDD faster, it is going to produce less heat and consume less
electricity because it has less moving parts.
Lesson of the day: When you buy a hard disk drive, always try to settle for the one with the least number of hard disk platters (highest data density).
SATA 3 Hard Disk Drive = Faster than SATA 2 Drive - False

It doesn't matter whether your hard disk drive is SATA 2.0 or 3.0 - It won't make a difference in hard disk performance.
Allow us to explain why: SATA 2 has a maximum real-world transfer rate of 300 MB/s while SATA 3 raises this maximum limit to 600 MB/s. However, even the wicked-fast 15,000 RPM drives are only able to achieve transfer speeds of about 200 MB/s. So whether the
drive is SATA 2 or SATA 3, you won't see a difference in hard disk speeds.
Imagine that SATA 2 is a highway with a maximum speed limit of 300 km/h while the SATA 3 highway has a higher speed limit of 600 km/h. Now picture your hard disk drive as a car - Since even the quickest super car is only able to hit a top speed of 200 km/h,
it doesn't matter if you're driving on the first (SATA 2) or second (SATA 3) highway... You'll still be traveling at 200 km/h.
Big Hard Disk Cache = Fast Hard Disk Speed - False
Next let's talk about hard disk cache (also known as hard disk buffer). Hard disk cache is like personal RAM for your hard disk - It stores frequently accessed data and is bleeding fast compared to than the rest of the hard disk drive.
Before accessing data from the hard disk drive (which is a slow poke), the operating system will first check if the data is already stored in the hard disk cache. If it is, then the computer will be able to access this data much quicker, therefore leading
to overall faster hard disk speed.
In the past when hard disk drives only had a miserable 1 to 2 MB of hard disk cache, it made sense to buy a drive with more cache because it would indeed be faster.
However here's the catch: Once you hit 8 MB of hard disk cache, the speed gains from having more cache are negligible. So whether your hard disk drive has 8 MB or 64 MB of cache, you're not going to see any real-world speed improvements. For more details,check
out this article on Tom's Hardware where they did a speed comparison of hard disk drives with different cache sizes.
Since even the cheapest and most humble of modern hard disk drives will have at least 8 MB of cache, disk buffer size is no longer a factor in hard disk speed.
- See more at: http://www.buildcomputers.net/hard-disk-speed.html#sthash.XjL6AzPr.dpuf

展开全文
• hard disk sentinel pro是一个硬盘监控工具。hard disk sentinel pro可以用来鉴别可能的硬盘问题、性能退化或者硬盘错误，它的目标是寻找，测试，诊断和修复磁盘驱动器的问题，报告和显示SSD和硬盘健康，性能下降和...
• Windows 下硬盘复制工作，可复制加密，隐藏分，可作全盘的复制。
• bootkill clear hard disk
• Summary Original hard disk Reference ...My white Dell laptop cannot switch on anymore, decided to dump it, and retrieved the hard disk, bought a external hard disk and converted it into...


Summary
Original hard disk
Reference

Summary

My white Dell laptop cannot switch on anymore, decided to dump it, and retrieved the hard disk, bought a external hard disk and converted it into a portable hard disk, it is working properly.

Original hard disk

It’s important to remove the connection cap to expose the SATA serial port.

Below shows the picture of the cap to be removed.

After put inside the portable case.

Reference

绿联taobao


展开全文
• <div><p>can you add support to hard disk serial number? <p>in windows the command is - "wmic diskdrive get serialnumber" <p>it's different from - "wmic logicaldisk get VolumeSerial...
• hard disk介绍，讲解了一下harddisk相关的知识，文件系统的知识
• virtual hard disk 2009年的印象： 曾经有过一段时间，徘徊于对虚拟机硬盘格式的迷惑中，2009年，终于得出了一些结论（下面的思路基本通用于其他虚拟机） 搜了下，发现大部分用qemu或者kvm的...


virtual hard disk

2009年的印象：
曾经有过一段时间，徘徊于对虚拟机硬盘格式的迷惑中，2009年，终于得出了一些结论（下面的思路基本通用于其他虚拟机）

搜了下，发现大部分用qemu或者kvm的，都默认使用qcow2来作为虚拟硬盘，但qemu官方默认是用raw。下面是qemu wiki对两种格式的描述：rawRaw
disk image format (default). This format has the advantage of being
simple and easily exportable to all other emulators. If your file system
supports holes (for example in ext2 or ext3 on Linux or NTFS on
Windows), then only the written sectors will reserve space. Use qemu-img
info to know the real size used by the image or ls -ls on Unix/Linux.qcow2QEMU
image format, the most versatile format. Use it to have smaller images
(useful if your filesystem does not supports holes, for example on
Windows), optional AES encryption, zlib based compression and support of
multiple VM snapshots.raw的优势（能找到的相关资料太少，不知道是不是理解有误）：1、简单，并能够导出为其他虚拟机的虚拟硬盘格式2、根据实际使用量来占用空间使用量，而非原先设定的最大值（比如设定最高20G，而实际只使用3G）。——需要宿主分区支持hole（比如ext2 ext3 ntfs等）3、以后能够改变空间最大值（把最高值20G提高到200G，qcow2也可以，不过要转为raw）4、能够直接被宿主机挂载，不用开虚拟机即可在宿主和虚拟机间进行数据传输（注意，此时虚拟机不要开）而qcow2的优势：1、更小的虚拟硬盘空间（尤其是宿主分区不支持hole的情况下）2、optional AES encryption, zlib based compression and support of multiple VM snapshots.另外，根据fedora12的wiki，说测试结果是raw比qcow2性能更好，即使是新版的qcow2。http://fedoraproject.org/wiki/Featur...w2_Performance如果单纯靠这些信息，那么raw好像更有优势，而且更方便。（raw支持快照否？？？）那么，为什么大家都默认使用qcow2呢？为什么？同样的，还有vmdk vdi等虚拟机硬盘格式的优劣表现在哪方面呢？又看到一个资料，说raw 格式是一种”直读直写”的格式,不具备特殊的特性。也就是说，qcow2具备的这两个AES encryption, zlib based compression，raw就没有。kqemu是qemu的内核加速模块，不是kvm。wiki里qemu部分有写，和kvm是分为两部分的，是两种不同的内核加速模块。qemu跑98、me、xp是很慢的，但跑win95，win2000，是飞速的，尤其是win2000（nnd，win2000好像在普通电脑里相比那几个好像是最慢的）。98、me要快，可以用定制版的windows，好像叫lite的。
2010年的印象：更进一步认识，并修正上面的看法
但今天（2010年）再回过头来看，发现其实raw更好：
raw相比qcow2就缺乏的四个功能，但都能通过别的方式解决：1、加密功能：把raw本身就当普通文件加密之搞定2、快照功能：把raw加入版本管理目录中，具体需要的设置可能稍微有点多。3、宿主机不支持按需打孔模式（hole）：这个可以自己根据使用情况来扩展raw的最大值
4、硬盘压缩：就当普通电脑文件压缩之即可而raw有qcow2所无法媲美的功能：1、效率高于qcow22、直接读写虚拟机硬盘里面的文件，这比较“暴力”，但既然可以这么暴力，那么也就不怕虚拟机出任何问题了。

3、通用性好，是转为其他虚拟机的格式的通用中间格式，这样就不用担心转换虚拟机系统了。

==================================================================
补充一：
如何让KVM等各种虚拟系统能够拿到本地硬件的原始级别图形加速功能：
在linuxsir上playfish提到：可以让kvm拿到native级别的图形加速性能。目前我对spice仍然不熟，感觉就是一个虚拟机统一后端/前端图形界面，但这个用远程桌面不也可以实现？（已经被我下面的否定了，两者不一样，spice应该是：远程桌面+远程资源本地映射）刚刚看了其英文介绍，简要翻译下：硬件加速方面：1、“客户端”2D使用通用的Cairo渲染2、“客户端”windows下使用GDI，linux下使用Opengl3、使用“客户端”的GPU来替换CPU渲染：可因此获得高效的渲染，并改善虚拟机的CPU使用率4、“服务端”使用Opengl来渲染ps：这很好玩，不管虚拟的机子是什么类型，都可以根据自己电脑的配置，来使用本地的硬件，那这样的话，同样的一个虚拟机，在不同的电脑上显示效果可就不一样了。

==============================================================补充二：
虚拟硬盘所在的宿主机分区该使用何种分区方式？问题的关键可能是虚拟机的虚拟硬盘到底保留了多少宿主机的分区格式特点了。比如宿主用ext3,而虚拟机里用ext4,那么虚拟机里面的性能如何？是 ext3的性能还是ext4的性能？——我想可能ext3的性能应该是该虚拟机的最高上限了，而不会有ext4提升的那部分。硬盘的最大性能>特定分区格式和系统所能利用的最大性能>虚拟机虚拟硬盘所能利用的最大性能>虚拟机中的操作系统和分区格式所能利用的 最大性能 经过这么多层的削弱，估计确实非常有必要有一种专门为虚拟机设计的分区格式，比如lvm之类的，来获得更高的性能。 虚拟机中，linux的swap还是要开的，因为你无法确定某一天你会大量使用内存（尤其是用于服务器方面的），以至你原来给的内存不够用，所以需要预留这些空间，有了这点缓冲时间，估计够在线解决问题了。 但挂了swap之后慢，可能和我上面说的：虚拟机的硬盘性能最大只能达到宿主的硬盘性能上限，而不会超过它，所以导致的。

========================================================
补充三：
raw在生产环境下也这么好？
并非如此，因为我所上面列举的4个raw可以通过别的方式搞定的功能，实际上有个前提：能够随时关机。（不关机也可以，但因为这方面并没有经过多少验证，安全性稳定性如何存疑。）
而raw的很多优势，也是基于关机状态才具备的优势，比如：直接挂载。而这些都是生产环境下所无法具备的条件，生产环境大都需要的是：在线方式实现／不关机就可搞定（即使是硬盘分区之类底层操作，所以才会发展出lvm之类的东东）。
也就是说，如果要在线具备更高级的硬盘特性／稳定性／有保障的品质追求，那么raw可能不是个好选择。
2012年的新看法：qemu可支持的类型，比较全面，呵呵。raw (default) the raw format is a plain binary image of the disc image, and is very portable. On filesystems that support sparse files, images in this format only use the space actually used by the data recorded in them.cloop Compressed Loop format, mainly used for reading Knoppix and similar live CD image formatscow copy-on-write format, 历史原因，但在视窗操作系统上不支持qcow the old QEMU copy-on-write format, supported for historical reasons and superseded by qcow2qcow2 QEMU
copy-on-write format with a range of special features,  including the
ability to take multiple snapshots, smaller images on  filesystems that
don't support sparse files, optional AES encryption,  and optional zlib
compressionvmdk VMware 3 & 4, or 6 image format, for exchanging images with that productvdi VirtualBox 1.1 compatible image format, for exchanging images with VirtualBox.

posted on 2014-09-03 15:22 秦瑞It行程实录 阅读(...) 评论(...)  编辑 收藏

转载于:https://www.cnblogs.com/ruiy/p/vhd.html
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