McGuffey@DOCKMASTER.ARPA (MAJ David McGuffey) (01/04/89)
#9 (6 lines in body):
Delivery-By: Network_Server.Daemon (KPETERSEN@WSMR-SIMTEL20.ARMY.MIL)
Sender: KPETERSEN at WSMR-SIMTEL20.ARMY.MIL
Date: Tuesday, 3 January 1989 13:25 est
From: Keith Petersen <W8SDZ at WSMR-SIMTEL20.ARMY.MIL>
Subject: Z-205 memory boards
To: yang at FRITH.EGR.MSU.EDU
cc: mcguffey at DOCKMASTER.ARPA
In-Reply-To: Msg of 30 Dec 1988 21:07-MST from yang at FRITH.EGR.MSU.EDU
I don't think Info-HZ100 will be of much assistance in answering your
Z-158 question. The more appropriate group is
Heath-People@MC.LCS.MIT.EDU
--Keith
---(9)---
#14 (13 lines in body):
Date: Wednesday, 4 January 1989 06:30 est
From: MAJ David McGuffey <McGuffey>
Subject: Z-205 memory boards
To: McGuffey
Forum-Transaction: [1233] in the >site>forum_dir>hz100 meeting
Transaction-Entered-By: Network_Server.Daemon
Transaction-Entered-Date: 3 January 1989 07:10 est
From: McGuffey.SDI@DOCKMASTER.ARPA@RADC-TOPS20.ARPA
I have a Z-158 XT with 512K in the system memory board. My machine was
purchased with 256K and expanded to 512K. Now, I have one bank of 256K chips.
I want to put them into the machine to have total 768K memory. However, as my
understanding, DOS can only address up to 640K. What about excess 128K?
My hope is to use those 128K as expanded memory. I don't know your Z-205 is
capable to do such thing. (Memory Backfilling). Please reply to my at this
address or Bitnet address - 15360JIM@MSU.BITNET. Happy New Year!
-Jim
---(14)---
In-Reply-To: Msg of 30 Dec 1988 21:07-MST from yang at FRITH.EGR.MSU.EDU
I'm not sure what happened to my response to the message from yang, but his
original request appeared in the mailing list with my added comments stripped
off. Thus it appears that the request came from me. I'll try again.
Your 158 uses an IBM-PC/XT style bus and the Z-205 card for the Z-100 is for
an S-100 bus. The two are not compatible, not the same size/format and could
not be plugged into the other bus. As it comes from Microsoft and IBM, DOS
is restricted to 640k, because the video display area and some other things
use the memory between 640k and 1024k. The Z-100 uses a version of DOS which
has been modified by Zenith Data Systems for the Z-100. Since the Z-100 video
memory starts at a higher address (not compatible with IBM-PC/XT video), the
Z-100 can use memory all the way up to 768k. There are hardware/software
solutions that can fool the 158 (and most other IBM-PC/XT clones) into using
more that 640k, but this mailing list is not where you will find that
information. You also won't find it in the mailing list from heath-people
(most messages are about the old H-8, H-11, and H-89 machines). The best
place to seek answers to your questions is the info-ibmpc mailing list/digest.
I don't have their net address handy, but since you managed to get to this
list, I'm sure that you can find an address to the other list. Hope this
helps; sorry to clutter up this list with PC/XT (ug!) discussions.
dcm