Re: [midatlanticretro] Disk heads
- Oy! I just spend a summer figuring out to read one of those disk packs! (http://chrisfenton.com/cray-1-digital-archeology/)On Fri, Nov 18, 2011 at 4:19 PM, Mike Loewen <mloewen@...> wrote:
For those of you who never had the (dubious) pleasure of working on
removable pack disk drives, here are some pictures of a carriage assembly
with 6 heads and voice coil, circa 1974:
The 80MB disk pack for these drives looks like this:
My experience with this type of drive was with the HP 7920, 7925 and
7935, between '86 and '88. The 7920's capacity was 50MB, versus 120MB for
the 7925 and 404MB for the 7933. The 7920 and 7925 required an external
disk exerciser for head alignment after you replaced them, while the 7935
had a build-in diagnostic controller.
Mike Loewen mloewen@...
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/