21 Jun
2018
21 Jun
'18
8:49 p.m.
On 21 Jun 2018, at 16:00, Paul Winalski <paul.winalski(a)gmail.com> wrote:
[...]
for the microcode to customers. There were several
hacks in there to
slow down the disk I/O so that it didn't outperform the model 30.
Is this the origin of the lore on “the IBM slowdown device”?
I seem to recall there was also some trickery at the CPU level so that you could “field
upgrade” between two models by removing it but a) I cannot find the source and b) my Pugh
book is far and cannot scan through it.
Arrigo