Subject: Re:large disk platters?

From: Pierre Gebhardt <>
Date: Sat Feb 22 11:04:00 2003

Wow !

Tony, could you send some photos of your disk drive ?
I'd like to see this "mystical" thing ! :)
The 24" platters of IBM's RAMAC are known to me but 36" platters ???
Who could have built such disk drives ? Any ideas of the company ?


> > In about 1976 University of Missouri Bioengineering Program acquired an "IBM
> > surplus image system" from somebody "unknown" out west. They sent a couple
> [...]
> > There were two clamshell halves that were opened to access the platter, each
> > track had a fixed head over it. Stored on each track was the image on a
> > single display station. By switching between tracks you could access
> > different images. There was a vacuum pump to remove the air if you opened
> > the clamshells to adjust the heads. Each of the display stations had an
> > integrated keyboard and a proximity or optical pen to select menu items.
> One of the peripherals I have for my PDP11s is a PPL model 121 display
> system.
> It uses a magnentic disk to store the video images. I think it rotates
> once per field (the motor speed is electronically controlled with an eddy
> current brake IIRC). Images are stored using analogue FM modulation on 3
> tracks of the disk (one for each of R, G, B). There are several sets of
> fixed heads which can be selected so you can store several images on the
> disk and display them.
> The disk is a lot smaller than the ones described here, though. I've not
> taken the HDA apat (for obvious reasons), but it looks to be a normal 14"
> platter. The HDA fits, disk horizontal, into a normal 19" rack module.
> There's a separate PSU rack module, and a cardcage of electronics. It
> connects to the Unibus via a DR11B interface I think.
> -tony

Keine Lust, immer Ihre Adressdaten in eine E-Mail zu schreiben? Mit der
vCard ist Schluss damit! Infos -
Received on Sat Feb 22 2003 - 11:04:00 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:35:56 BST