carsontr@dgp.toronto.edu ("Carson T. Schutze") (08/17/88)
There was a fair bit of discussion a while back about the ALL
ChargeCard, especially since DesqView is now mentioning it in their ads.
In case you missed it, it's a little module which plugs into the motherboard
and which the CPU on an AT or higher plugs into, allowing > 640K for DOS,
converting extended to expanded memory, etc. by remapping the RAM in your
machine.
The one hesitation I have about buying it is a possible speed degradation.
What exactly is the performance penatly for interposing more address-decoding
logic between the CPU and the memory? Is there anyone out there who has
used this product and can relate their experience?
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Carson T. Schutze Dynamic Graphics Project
Computer Systems Research Institute
(416) 978-6619 University of Torontonews@pmt1.UUCP (Usenet news) (08/19/88)
In article <8808171456.AA12331@explorer.dgp.toronto.edu>, carsontr@dgp.toronto.edu ("Carson T. Schutze") writes: > > There was a fair bit of discussion a while back about the ALL > ChargeCard, especially since DesqView is now mentioning it in their ads. > In case you missed it, it's a little module which plugs into the motherboard > and which the CPU on an AT or higher plugs into, allowing > 640K for DOS, > converting extended to expanded memory, etc. by remapping the RAM in your > machine. > > The one hesitation I have about buying it is a possible speed degradation. > What exactly is the performance penatly for interposing more address-decoding > logic between the CPU and the memory? Is there anyone out there who has > used this product and can relate their experience? > I tried the all chargecard about 6 weeks ago. It appears to map memory very quickly from one dos region to the next. On the order of 50 nanoseconds if I recall correctly. I didn't do any heavy duty benchmarking, but didn't notice any speed degredation on a 10mhz PS/2 model 50 either. I was able to expand the DOS memory partition up to 960K when running plain DOS, with the balance of the first meg for video buffer area which is remapped. It also helped me squeeze a bit more memory out of Dos for existing application packages. Running with a VGA monitor I was able to expand DOS up to the base of the VGA video buffer which is believe was at 736K. Beyond that if the application writes to a hard coded address for video memory you run into conflicts. EGA, CGA, Mono have different video addresses so mileage may vary depending on the monitor used. The all chargecard comes with instructions to help you locate the hardcoded writes to video memory in stubborn applicaitons. For some releases of popular application packages there is a database of these patches which comes with the package. There are also tools to help you automate this process. For some releases and packages you will have to do your own patching with the help of the instructions in the user manual. We found that for some of the IBM systems software our customer would not accept such patching. So for one package we were limited to 736K dos partitions. For a second which was smarter about isolating itself from relocating the video buffer we could reclaim more of the 1 mb Dos partition. But when running the IBM token ring lan, parts of the lan software (network administration menus) it too was using a workarea above the 640K line. So even though one application could run with a 960K partition on its own, the lan software caused additional conflicts. You can dynamically change the dos partition size from a bat file using software which accompanies the all chargecard. So when using the Lan menus we downsized the Dos partiton before starting and increased the Dos partition size after ending the lan menus. I was unable to get the accompanying ram disk to function at all on an IBM PS/2 model 50. And the distributor finally admitted there was a problem, but no fix was provided. The all chargecard seems useful for 286 machines, but the size of the memory expansion varies with the particulars. On 386 machines it appears that the all chargecard is not needed - Quarterdeck appears to supply a driver with uses the 386 in a way that duplicates the benefites of the All Chargecard. It was expensive ($400+) from the dealer in New York. If you want Desqview, Quarterdeck appears to offer a much more attactive bundled package.
svirsky@ttidca.TTI.COM (William Svirsky) (08/20/88)
In article <8808171456.AA12331@explorer.dgp.toronto.edu> carsontr@dgp.toronto.edu ("Carson T. Schutze") writes:
+ There was a fair bit of discussion a while back about the ALL
+ChargeCard, especially since DesqView is now mentioning it in their ads.
+In case you missed it, it's a little module which plugs into the motherboard
+and which the CPU on an AT or higher plugs into, allowing + 640K for DOS,
+converting extended to expanded memory, etc. by remapping the RAM in your
+machine.
Does the ChargeCard actually fool DOS into thinking that it has > 640K
of contiguous memory? Is DOS written so that it can use > 640K of
contiguous memory? How are memory conflicts handled, such as when video
memory is accessed? Are there any, or any other, products (hardware or
software) that can do the above?
I'm working on a project in which we want to have 2 applications loaded
simultaneously in memory on a 286 or 386. One of the applications, a
3270 communications emulator, has a way of switching itself from
foreground (ie. in control of the PC) to background and back with a
single keypress. When it is in background, the other application, an
expert system, is in the foreground. These applications are large
enough that together they suck up most of 640K. We also need to have
the expert system, while it is in foreground, execute another program
under DOS. It has this capability, but it does it via DOS/command.com.
Currently, this works, barely. The problem is the knowledge base of the
expert system can grow. So we may exceed 640K in the near future. I
want to find a solution now, if one exists, rather than wait until we
run out of memory. Software solutions, such as Desqview, are fine, but
only if they allow an easy transition between applications, preferably a
single keystroke (or multiple simultaneous keystrokes). This system
will be used by an operator who should be unaware of any software but
the 3270 emulator and the expert system. So, having to open a menu,
choose from the menu, etc, is no good. If I get sufficient response,
I'll summarize and post. Thanks.
--- Bill Svirsky
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Bill Svirsky, Citicorp+TTI, 3100 Ocean Park Blvd., Santa Monica, CA 90405
Work phone: 213-450-9111 x2597
svirsky@ttidca.tti.com | ...!{csun,psivax,rdlvax,retix}!ttidca!svirsky