Hard disks
Hard disks consist of one or more magnetic disks contained in a box. They are used as storage media in
the PC, where you store programs and other digital data.
The magnetic storage hard disk is based on a 40 year old technology. It has been and still is being
improved rapidly. Hard disks continue to shrink in size, gain increased storage capacity and increased
transfer speeds. The development has been tremendous during the last 10 years. Indications are that this
will continue for a long time.
When buying a PC, It is a good rule to include a large and fast hard disk. You can never buy too large a
hard disk and the data transfer speed is decisive for the PC's performance.
An evaluation of the hard disk, its configuration and performance, involves several different technologies.
That is the subject of this page:
l The mechanical disk. The physical disk construction, RPM, read/write head, data density, etc.
The cache. The hard disk always has some cache RAM onboard. It serves as a buffer, so the data
being physically read is best utilized.
The interface. The connection between the hard disk and other PC components. That is called
interface - the connection to a data bus, the controller principle.
Formatting etc. Disk formatting, control system, cache, etc. I presume you are running in Windows
95, which has the best access to the hard disk.
I want to illustrate the inter-action between these features, thus giving a comprehensive picture of the hard
disk and its technologies.
Historic
First, let us look at the hard disk history. IBM introduced the first hard disk in 1957. That was a major
project. It consisted of 50 platters, 24 inch diameter, with a capacity of 5 MB, a huge storage media for its
time. It cost $35,000 annually in leasing fees (IBM would not sell it outright). The first model to use "float on
air" technology for the read/write heads was named Winchester 3030. So named because it was
developed in Winchester, England and had two sides, each of which could store 30 MB. To some people,
this designation was reminiscent of the famous Winchester 3030 repeating rifle.
Later, the disk platters shrunk to 14" and 8" diameter. They were installed in towers containing dozens of
these magnetic platters.
In the early years of PC development, the low cost floppy drives were the preferred storage media. But with IBM's XT in 1983-84, the hard disk became the preferred media. The first hard disks were rather large units (5.25" diameter) and of poor quality. I have replaced numerous 5, 10 and 20 MB hard disks during 1986-88, since these early PC hard disks had an incredible short life span. Since then they have improved a lot.
The modern hard disks ar3.5" diameter. A typical example is the Quantum Fireball, which you see above. The cover plate has been removed, so you can see the top arm with its read/write head.Hard disks can be found in much smaller sizes (all the way down to match box size). However, forordinary, stationary PC's the 3.5" is the best. They are inexpensive to manufacture, and they are faster.
Hard disks consist of one or more magnetic disks contained in a box. They are used as storage media in
the PC, where you store programs and other digital data.
The magnetic storage hard disk is based on a 40 year old technology. It has been and still is being
improved rapidly. Hard disks continue to shrink in size, gain increased storage capacity and increased
transfer speeds. The development has been tremendous during the last 10 years. Indications are that this
will continue for a long time.
When buying a PC, It is a good rule to include a large and fast hard disk. You can never buy too large a
hard disk and the data transfer speed is decisive for the PC's performance.
An evaluation of the hard disk, its configuration and performance, involves several different technologies.
That is the subject of this page:
l The mechanical disk. The physical disk construction, RPM, read/write head, data density, etc.
The cache. The hard disk always has some cache RAM onboard. It serves as a buffer, so the data
being physically read is best utilized.
The interface. The connection between the hard disk and other PC components. That is called
interface - the connection to a data bus, the controller principle.
Formatting etc. Disk formatting, control system, cache, etc. I presume you are running in Windows
95, which has the best access to the hard disk.
I want to illustrate the inter-action between these features, thus giving a comprehensive picture of the hard
disk and its technologies.
Historic
First, let us look at the hard disk history. IBM introduced the first hard disk in 1957. That was a major
project. It consisted of 50 platters, 24 inch diameter, with a capacity of 5 MB, a huge storage media for its
time. It cost $35,000 annually in leasing fees (IBM would not sell it outright). The first model to use "float on
air" technology for the read/write heads was named Winchester 3030. So named because it was
developed in Winchester, England and had two sides, each of which could store 30 MB. To some people,
this designation was reminiscent of the famous Winchester 3030 repeating rifle.
Later, the disk platters shrunk to 14" and 8" diameter. They were installed in towers containing dozens of
these magnetic platters.
In the early years of PC development, the low cost floppy drives were the preferred storage media. But with IBM's XT in 1983-84, the hard disk became the preferred media. The first hard disks were rather large units (5.25" diameter) and of poor quality. I have replaced numerous 5, 10 and 20 MB hard disks during 1986-88, since these early PC hard disks had an incredible short life span. Since then they have improved a lot.
The modern hard disks ar3.5" diameter. A typical example is the Quantum Fireball, which you see above. The cover plate has been removed, so you can see the top arm with its read/write head.Hard disks can be found in much smaller sizes (all the way down to match box size). However, forordinary, stationary PC's the 3.5" is the best. They are inexpensive to manufacture, and they are faster.
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