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Tuesday, December 04, 2007

1956 5 MB External Hard Drive

The 350 Disk Storage Unit consisted of the magnetic disk memory unit with its access mechanism, the electronic and pneumatic controls for the access mechanism, and a small air compressor. Assembled with covers, the 350 was 60 inches long, 68 inches high and 29 inches deep. It was configured with 50 magnetic disks containing 50,000 sectors, each of which held 100 alphanumeric characters, for a capacity of 5 million characters.

Disks rotated at 1,200 rpm, tracks (20 to the inch) were recorded at up to 100 bits per inch, and typical head-to-disk spacing was 800 microinches. The execution of a "seek" instruction positioned a read-write head to the track that contained the desired sector and selected the sector for a later read or write operation. Seek time averaged about 600 milliseconds.

With storage capacities of 5 million and 10 million digits, and the capability to be installed either singly or in pairs, the 350 provided the 305 system with storage capacities of 5, 10, 15 or 20 million characters.

An IBM RAMAC 305 with a 350 disk storage unit leased for about $3,200 per month back in 1957. Over a thousand of the 305 systems (one of IBM's last vacuum tube units) were manufactured before production ended in 1961, and the 305 was withdrawn in 1969.
-- Snopes - Computer Storage

Weighed over a ton. Maybe I'll stop cursing at my Lenovo Thinkpad now.

(nah, I'll keep cursing at it)


Mark said...

I used to work at a research company that had one of the first computers, it ran 24x7 because it was composed largely of vacuum tubes and when shut off/restarted about half of them would burn out.

We were one of the first companies to get them new fangled IBM-PC's though. They came with a whopping 64k of memory,green monochrome screen and a cassette drive for data storage. The twin 360k floppies held whole programs such as DBASE, VisiCalc and Volkswriter (I kid you not).

The kicker was that only 2 computers on roll-around carts were authorized for a group of 12 engineers as management felt any more would be a complete waste.

And this was in the early 80's, it is truly amazing how far we have come in only 25 years.

Josh said...

Yeah, I still remember my dad spending an ungodly amount on something which could only laughably be considered a laptop these days....