[Info-vax] Microsoft: Alpha architecture responsible for poor Windows file compression

[terry-groups at glaver.org]

On Wednesday, November 2, 2016 at 6:28:51 PM UTC-4, johnwa... at yahoo.co.uk wrote:
> They ended up with one or two crashes a week per control
> room due to memory parity errors. That was unacceptable
> to this VMS customer so they were replaced with similarly
> configured AlphaServer 1000s which had ECC rather than
> parity. The single bit memory errors which crashed a box
> with parity memory were still occurring, but they were
> invisible to the software on a box with ECC memory, the
> system just kept on running.

This sure sounds like a design error, incompatible add-on
memory, or an out-of-spec operating environment. I had quite
a few AS200 4/233 systems maxed out w/ 768MB, where I would
expect to see problems if something was marginal, and they
worked just fine.

A common issue at that time was using SIMMs with the wrong
connector material. There were two types, gold and tin (sol-
der). Sockets for tin SIMMS had sharp points on the pins to
make an air-tight seal (similar to how wire-wrap works). If
you put a gold SIMM in a socket designed for tin SIMMs, the
pins in the socket would "stub their toes" on the harder
material and become deformed, so even replacing the SIMM
with the correct tin one would no longer be reliable. You
may be saying "gold is harder than tin?", but the gold was
plated directly onto the copper of the PCB and that's where
the problem came from.

However, all bets were off with "PC" type hardware. There
was a proliferation of processor support chipset brands and
some of them had problems. I had a coversation (via an in-
terpreter) with the lead designer of one brand (unnamed, but
sounds like "sympathy" 8-) where he flat-out told me he did
not care about cache consistency errors because "Windows 
wouldn't stay up that long anyway". Unfortunately, I was 
using BSD/OS and one system from that era eventually showed
the uptime as "***" as it had overflowed the 999 days the
utility would display. Somewhat later, the market was treat-
ed to the "COASt fiasco" which also introduced gratuitous
cache errors.