phipps@garth.UUCP (Clay Phipps) (12/20/88)
I understand the aggravation of some at seeing the news-group bandwidth
used for repetition of common questions. Despite my repeatedly marking
the original queries as "unread", they disappeared before I could answer.
However, I will risk the flames on this and another item,
because the information requested is on hardware that is not widely
available any more (I think that it is out of production).
Someone posted a request for information on expansion boxes
that allowed display adapters to work properly when transferred
to the expansion box. Such boxes exist; I have one.
Sigma Designs (Fremont, CA; area code 415) manufactures 2 expansion boxes
for the IBM PC: the EWS-0000 (4 zeros) with 9 slots, and MWS with 5 slots.
I believe that they also make models (-0100 ?) for the XT.
Don't expect to find big discounts -- I looked around Silicon Valley and
the S.F. Bay and Sacramento areas. Production never reached a high
volume, it seems; for most individual and business purchasers,
especially those who depreciated original PCs away, outright replacement
by AT-clones became a more attractive option than expansion boxes.
The EWS-0000 lists for ~$800 -- much more than the ~$400 box described
in the original posting, but far less than the ~$2000 for true-blue IBM.
Everex claims that "all slots in the expansion [box] can be used for any
cards". One is needed in each box for driver (i.e., connection) cards.
I have moved all cards from my system box to my EWS-0000 expansion box,
except the floppy controller card and the IBM Asynch Adapter.
It's too much trouble to uproot the former from the floppy drives,
and the latter fails to pass IBM diagnostics while in the expansion box.
The latter problem should be able to be resolved, but I haven't bothered.
As I understand things, whether the display adapter will function
properly in the expansion box depends on whether the expansion box
supports direct memory access (DMA) -- the cards work only if
the expansion box supports DMA. The Sigma boxes do;
the original posting suggests to me that the ~$400 box does not.
The bottom line: is the flexibility of DMA support by the Sigma Designs
expansion box worth the extra $300..$400 ? To me, it was;
to others, it may not be.
Either way, you will still probably need a ROM upgrade to make an
original PC support hard disks -- try low-to-medium-volume retail outlets.
I have no connection with Sigma Designs except as a customer.
--
[The foregoing may or may not represent the position, if any, of my employer]
Clay Phipps {ingr,pyramid,sri-unix!hplabs}!garth!phipps
Intergraph APD, 2400#4 Geng Road, Palo Alto, CA 93403 415/494-8800