🚀 go-pugleaf

Chung-Hsiung Yang (chyang@quip.eecs.umich.edu) wrote:
: In article <rbarris-2909951107340001@192.168.1.16>,
: Rob Barris <rbarris@quicksilver.com> wrote:
: >
: >Over 50 companies have made their PCI products available on Power
: >Macintosh. Among these are some companies like:
: >
: >  qLogic
: >  Adaptec
: >  DPT
: >  ATTO
: >  WD
: >  FWB
: >
: >(These are just the ones that make Mac-compatible PCI SCSI controllers,
: >contrary to the posting above).
: >
: >I found the other assertions to be completely unfounded, it is a very rare
: >SCSI device that I can't plug into my Mac.  In our office alone we have
: >drives from Quantum, IBM, Conner, Micropolis, Seagate, plus CDROM drives
: >from Sony, Matsushita, Hitachi, Panasonic, and JVC. These all work on the
: >Mac.

: 	Yes, I forgot to add that Apple did do a complete overhull
: of their hardware design about 2years ago to "conform" to more of an 
: "industry standard".  So many of the incompabilities are gone.  They
: finally decided that why yes, we *should* use the same memory modeules
: and devices controllers as everyone else to cut cost ( among other things).
: By then try putting a 72pin Simm into my trusty Q700 then you'll know 
: the problem. ( Damn!  I love that machine.  But God forbid if I try 
: to expand that thing ).   And yes, the PCI bus ( which was designed by 
: Intel BTW ) was incorporated out of market pressure. 

Uh, I beg to differ.  My 1989 Mac IIci which is over SIX years old
works with a variety of SCSI devices not made for the Mac, including
hard drives, CD-ROM drives and tape drives.  I've never had a problem
with it.  

Your comment about the Quadra 700 is either disingenuous,
or you have little knowledge of the last four years of computer
hardware history.  The Quadra 700 uses standard 30 pin 8 bit SIMM's,
the same ones used in Mac's from 1986 until about 1992, and it
will work just fine with 30 pin 9 bit SIMM's which were used in
almost all 80386 machines, and most 80486 machines (excepting the
3 chip, 30 pin, 9 bit SIMM's, get the nine chip ones).  Mac's
were standardized on SIMM's when many PC's were still experimenting
with DIP's and SIP's or required a special board to expand memory.

Because the 30 pin SIMM's only supply 8 bits at a time, four of
them were needed to supply CPU's that had 32 bit data buses.
That is why they are installed in fours ( or pairs for older
68000, 80286, and SX based machines which are 16 bit).  With
the advent of 64 bit data buses in newer CPU's, we would have
needed to install 30 pin SIMM's EIGHT at a time.  this would
be inconvenient, and make upgrading a nightmare.  Plus motherboards
with fewer SIMM sockets are cheaper to make.  So Apple started
useing 72 pin 32 bit SIMM's, which are installed one at a time
for 32 bit data bus CPU's, in their newer machines.  This cut
motherboard costs and made upgrading simpler.  With the advent
of the Pentium and the PowerPC, both Macs and PC's went to 
72 pins so that we could install SIMM's 2 at a time instead of
8 at a time.  Since 72 pin SIMM's were the new standard, new
models with old CPU's, i.e. newer 80486 machines, used the
new 72 pin standard instead of the 30 pin standard.

But the switch to 72 pin SIMM's is a recent occurence and theere
is nothing non-standard about 30 pin SIMM's in a 1992 model 
computer.