LOU wrote on Jul 11^th, 2011 at 3:08pm:

Mark & Michael, It is kinda fun to look back at the things we thought as "modern" computers. The hard drive on this IBM-360 had four or five platters in a stack, each separated by about an inch or so. To change hard drives you would use a large plastic cover that looked like a really big cake cover. You would place the cover over the drive stack and screw the cover down onto the hard drive. Then you would pick up the whole hard drive and replace it with another drive which had another airlines data on it. Lou

Ah yes the wonderful 2311 disk drive, when I got to HQ USMC in the early 70's they had upgraded to the 2314 "pizza ovens". Twice the platters and the actual drives looked just like a big pizza oven.

The worst disaster possible was a head-crash, the read writes heads making contact with the actual platter. Of course the system would ask you to change the pack to another drive. If you did without checking the surface, you would destroy the heads on the new drive.

There was a micoswitch which prevented the drive from spinning up if someone left the cover on the drive and closed the door.  :o
Someone left a cover on and the switch was bad. When the read-heads slammed into the cover the noise was horrendous. Scratch one drive and disk pack.

Our mainframe has 256k of core memory, we added 2megs of "low" read slow and external memory. ;D

the good old days,

Bruce