joel@rochester.UUCP (12/07/84)
From: Joel Seiferas <joel>
Thanks to STB, my problem with the IBM Enhanced Graphics Adapter
is solved, and my system now passes diagnostics with flying colors.
The problem was with the STB SUPER RIO board that holds 576 of my 640
kilobytes of main memory. Although I had installed no memory in any of
the reserved regions (above A0000), the board apparently was responding
in some way to memory requests up there. STB promptly sent me a couple
of prospective replacements for their memory mapping chip, one ignoring
the 64K starting at A0000, and the other ignoring this bank and also
the ones starting at D0000 and E0000. Being in no mood to experiment,
I chose the latter to try, and it solved the problem.
One conclusion worth noting is that the ROM BIOS chip dated
exactly "10/27/82 x" does work fine with the EGA.
So far, I have run into no problems with the compatibility of the
EGA; but I have not tried anything exotic. (IBM's LOGO seems okay.)
The EGA includes almost 16K of new ROM code, starting at address
C0000. For hints on how to use this ROM, one could disassemble the
8692 bytes of diagnostics code in US1ADG2.DGS, on the diagnostics
diskette (version 2.07). If anyone does this, please post the results!
For a start, I'd expect at least to be able to switch to and use the
43-line mode on the monochrome display, at least while in DOS.
An unusually timely report on the EGA can be found in the current
issue (12/25/84) of PC Magazine, starting on page 171. In addition to
kind sympathy, a few interesting technical tidbits were included in the
messages I have received since I asked for help. I'll attach some of
these messages to the end of this report.
Joel Seiferas
> #: 75156 Sec. 1 - User Updates/Fixes
> Sb: Enhanced Graphics Ad.
> 29-Nov-84 22:08:24
> Fm: STEVE BEAN 70575,406
>
> You will have to set the board type (switches 5 and 6 SW1) to no graphics
> board (both on) in order to get the beast to work. Once you get it working, you
> will discover an interesting thinga ctrl-alt-del reset takes much longer
> because apparently you are thrown back into the cold start boot rather than the
> warm boot which you used to get. Why??
>
> The enhanced graphics board contains a "rom cartridge". The newer ROM contains
> routines which look into memory starting at c000:0 for the bytes 55 aa which
> indicate the presence of a "game cartridge". Definition of the rom stuff is in
> the pcjr tech ref manual. The rom on the enhanced graphics board replaces int10
> and puts the call to old int 10 at int 43. One interesting note is that rather
> than fetching the vector at int 10 and placing it at int 43, they stuff the
> address of the entry to the video io call in the ibm rom into int43. If a
> "compatible's" rom is not exactly the same as the ibm (same entry address),
> putting an enhanced board in it will bomb.
>
> #: 75260 Sec. 3 - PC-AT
> Sb: EGA
> 30-Nov-84 04:26:23
> Fm: Zhahai Stewart 74076,252
> To: all
>
> I just got an Enhanced Graphics Adaptor. I called all of the local dealers and
> product centers and one called back a short while later and said they had just
> gotten in a shipment of them. By the way, one of the IBM product centers was
> very misinformed about the board.... Anyway, I now find that the real
> technical meat (ports, memory addresses, etc.) must be found in an update to
> the "options and adaptors tech ref manual", which costs $125!!! This is a two
> volume set, so perhaps the cost is not terrible if I was interested in other
> adaptors, but I find it outrageous for the little I want to know. Does anyone
> know if there is another channel to getting JUST the technical info on the EGA?
> (ps: I have the seminar proceedings, but they do not give quite enough).
>
> #: 75703 Sec. 3 - PC-AT
> Sb: Enhan Graphics Report
> 02-Dec-84 11:18:26
> Fm: Bob Fritts 70156,220
> To: All
>
> I have the Enhanced Graphics adapter running on a 9Mhz AT with the old
> (640x200) color display. The card is an 8 bit card so that it can also be used
> on the PC or XT. Therefore, the speed of scrolling is the same as for the old
> graphics adapter. So far, the only program that I have that does not run is
> LO-RES.EXE by Marty Smith. I assume that is because the EGA does not support a
> 160x100 mode. The MODE command no longer permits a shift or test pattern!!! So
> far, the old "Chromablizzard" is gone, and the screen is much cleaner when
> doing a screendump. There is no way to get 9x14 text until the Enhanced Color
> display 5154 is available, and no need to get the piggyback unless you want
> 640x350 graphics, as 16 colors are supported in text mode at 640x350.ee161abt@sdcc13.UUCP ({|stu) (12/09/84)
> > There is no way to get 9x14 text until the Enhanced Color > > display 5154 is available .... Could anyone tell me if the Princeton SR-12 is the same as the Enhnaced Color Display. Spec's: 31.25 KHz, 690 X 480 non-interlaced, lists for $799, and it sure looks like the one IBM sells.