[TUHS] Old mainframe I/O speed (was: core)
arrigo at alchemistowl.org
Fri Jun 22 00:49:21 AEST 2018
On 21 Jun 2018, at 16:00, Paul Winalski <paul.winalski at 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.
More information about the TUHS