AnotherFairportfan wrote:Dave wrote:GlytchMeister wrote:*shudders*
Washing machine-sized drives that wobbled like washing machines.
*shakes head*
As well you should. The motors which moved the arm assemblies back and forth across the layers of players, were bigger and heavier than most of today's entire disk drives.
There was a story, at a school district computer center where I worked for a while, about an accident involving one of those big drives. It was undergoing a maintenance alignment of some sort... spinning, with the protective top cover in the open position... when the technician dropped some ash from his cigar into it (this was back in the day before no-smoking regulations, and perhaps before common sense had evolved past the amphibious stage). The central bearing siezed, and the rotating torque of the disk threw the disc across the room like a flying guillotine.
Probably too good a story to be literally true, but like many such it contains a kernel of truth. Those disk packs weren't light...
half a dozen rigid aluminum platters 14" in diameter, spinning at about 1800 RPM. When in operation they needed to be treated like the industrial devices that they were.
Sometimes, fixed-head disks were used... trading off capacity and cost and electrical complexity for faster access.
One system I used in college had a RAD which was used entirely as a swap device... a full-sized cabinet, with about as much memory capacity as exists in the on-chip L3 cache of a modern CPU.
FASTRand, which i've mentioned, was basically a section of sewer pipe, filled with concrete and coated with oxide.
They rotated at 880 RPM.
The first FASTRand was a single-drum unit, and was quickly succeeded by FASTRand II, which had teo counter-rotating drums - the single-drum unit; Wikipedia says:
The large mass of the rotating drum caused gyroscopic precession of the unit, making it tend to spin on the computer room floor as the Earth rotated under it. Very few of these devices were delivered.
and
The Fastrands were very heavy (5,000 pounds) and large, approximately 8' long. Due to their weight, FASTRAND units were usually not installed on "false floor", and required special rigging and mounts to move and/or install. There were reported cases of drum bearing failures that caused the machine to tear itself apart and send the heavy drum crashing through walls*.
Specs:
Specifications (FASTRAND II)
Storage capacity: 22,020,096 36-bit words = 132,120,576 6-bit FIELDATA characters = 99 megabytes (8-bit bytes) per device
Drum rotation rate: 880 RPM (14.7 rotations per second)
Heads: 64
Sector size: 28 36-bit words
Track size: 64 sectors (1,792 36-bit words)
Track density: 105 tracks per inch
Average Access time (seek time plus rotational latency): 92 milliseconds
Data transfer rate: 26,283 36-bit words per second = 118 kilobytes per second (8-bit bytes) on 1100 series machines
Recording density, one-dimensional: 1,000 bits per inch (along one track)
Recording density, two-dimensional: 105,000 bits per square inch of drum surface
Max FASTRAND devices (drum units) per controller: 8
Controller price: $41,680 (1968 dollars)
FASTRAND device price: $134,400 (1968 dollars)
Weight per FASTRAND device: 4,500 pounds
Weight per kilobyte: 6 ounces (170 g)
{The BLS CIP Inflation Calculator says that$176,000 in 1968 is roughly $1,271,000 today.}.
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* One of the stories about bearing failures told of a night shift, the operator as (luckily for him) sitting leaning his chair back on two lege, feet on the desk, when the bearings seized and the drum came crashing through the front of the cabinet and shot across the floor, cutting the back legs out from under the chair; about the time he hit the floor, the drum had buried itself halfway into the opposite wall...