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Old 12-16-2002, 04:26 PM
astro astro is offline
Join Date: Jul 1999
History and age of the "can" cylinder icon/symbol being used for data storage

My daughter asked me this because the light on the bezel of her PC was flashing as the hard drive was accessed under what she called the "can" symbol. I told her that it was the symbol for the hard drive and if I recalled correctly was used as far back as my Computer Science 201 class (circa 1979) in college when flowcharting.

How old is this symbol and why is it a cylinder/"can"?
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Old 12-16-2002, 05:14 PM
sailor sailor is offline
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Join Date: Mar 2000
I believe the cylinder actually represents a stack of disks which are the platters of a hard disk. And we are talking when hard disks were huge, as in over a foot in diameter.
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Old 12-16-2002, 05:15 PM
Armilla Armilla is offline
Join Date: Mar 2001
I can't really say how old the symbol is, but I can make a few guesses as to its origin.

Some early computers used a magnetic drum as their memory/storage device. An example is the 1960 vintage Royal McBee LGP-30 that spawned the tale of Mel, a real programmer.

This page shows a picture of a 1956 IBM 305 RAMAC computer with one of the first harddisk units. In the picture you can clearly see the stack of fifty 24" disks behind the operator. This was a step forward from drum storage devices, but the overall package was still pretty drum shaped.

Later computers used sets of disks more like a modern harddisk if you overlook the fact they were eighteen inches across and were heavy enough to crush the fingers of unwary technicians. These were often kept in stacks of four or more in plastic caddys that could be swapped around in the drive cabinets. In this assembly they looked like short cylindrical drums with a handle at the top. I've seen versions of the harddisk symbol, mainly on older equipment, that refelected this structure by having a number of curved lines along the body of the "can".

As technology has got better things have got smaller so that now the set of disks is far shorter than it is wide, or is even reduced to a single platter, and is anyway sealed from sight inside the metal body of the unit.

Based on this I'd guess that the origin of the symbol probably dates to around 1955-1960 and probably came from some kind of IBM system documentation. It's a fairly logical icon based on the hardware they were using, so I imagine it came into being along with the early hard disks. I stress that this is just a guess though; it could easily have originated with the earlier drum based storage devices, but IBM invented pretty much everything else to do with computers and I'm blaming them for this too.
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Old 12-16-2002, 05:34 PM
Finagle Finagle is online now
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Sounds right. And for years, the symbol for input was a punched card -- a rectangle with a bevel cut along one corner.
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Old 12-16-2002, 05:42 PM
sailor sailor is offline
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God do I feel old. I remember when the first hard disks were called "Winchester" drives. Some random quotes:

IBM invented disk storage and shipped the first model in 1956. With a 24 inch diameter it stored 5M bytes

1973: IBM introduces the IBM 3340 hard disk unit, known as the Winchester

IBM introduced the Model 3350 disk drive, which had eight platters and weighed over 50 pounds. This was the only way IBM could achieve a 314MB storage capacity at that time. Thus, the removability requirement was abandoned and the first fixed hard disk drive was born.
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Old 12-16-2002, 06:13 PM
happyheathen happyheathen is offline
Join Date: Nov 2001
Posts: 2,394
I can place the symbol back to the late '60's/early 70's.

(yes, I'm old)
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Old 12-17-2002, 11:40 AM
ftg ftg is online now
Join Date: Feb 2001
Originally posted by sailor
God do I feel old. I remember when the first hard disks were called "Winchester" drives. Some random quotes:


1973: IBM introduces the IBM 3340 hard disk unit, known as the Winchester
Umm, the first hard disks were called "disks" (and "diskpacks" etc.). They weren't in sealed enclosures. "Winchester" was one early type of sealed disks. Since your post indicates that "Winchester" dates from the '70, didn't you wonder what they were called for nearly 2 decades before that?

The can symbol was on flowcharting templates by the mid-1960s.
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Old 12-17-2002, 11:48 AM
Alereon Alereon is offline
Join Date: Jul 2001
On early computers and documentation I've seen, the symbol is much more realistic, being wider than it is tall. This actually resembles the HDD platter array in a standard drive. My WAG is that the cylinder or can look is simply a stylized form of the original.
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Old 12-17-2002, 11:49 AM
sailor sailor is offline
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Join Date: Mar 2000
Actually I meant to say the first PC hard drives. I never really knew the mainframe disks but I remember the first PC hard drives were called Winchester drives to distinguish them from the floppies. I do not really remember when the term Winchester disappeared.
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