🚀 go-pugleaf

In article <1990Sep11.211524.2956@ultra.com> shj@ultra.com (Steve Jay) writes:
>In <1990Sep11.034940.16212@ecn.purdue.edu> 3ksnn64@cadlab.ecn.purdue.edu (Joe Cychosz) writes:
>
>>The unit had 4 quadrants.  The quadrants were organized into a upper
>>half and a lower half.  Each half used equal and oppsite positioning
>>to conteract arm movement.
>
>I think this is confusing the 6603 with the slightly later 6638.  The 6603
>had just one positioner which moved all the heads in the same direction
>at the same time.  I seem to remember the term "quadrants" associated
>with the 6638.  The rest of the info on the 6603 matches my recollection.

Yep!  A few more update facts and corrections.  As time goes by, the
numbers are all just a blur.

6603, had 39"x1/2" magnisium platters.  In each half there were 7 platters
(1 clock and 6 data/12 sides) rotating vertically.

A later drive, the 808 had 72 26" alluminum platters.  We had some of these
at Illinois also and I have a platter out of this.  This drive like the
later 6638 was devided into quadrants.  I believe there were about 10
of these drives made.

6638, don't know what size platters, was 800 Mbit drive and had 4x18
platters.  The disks spun at 1200 rpm and unlike the 808 used equal
and oppisite positioning as noted above.

>
>The 6603's claim to fame was its very fast (by 1966 standards) transfer
>rate: 1.4 Million 12 bit words a second (I think).  It did this by
>reading/writing 12 heads in parallel.  Average access time: ~200
>milliseconds, average latency: 32 milliseconds (900 RPM), so you had
>to wait a while before you saw the high transfer rate.