Strange issues with games on my XT

[m1k3e]

Ahhh, so I finally got around to tinkering with my XT. I put PC DOS 3.20 on there, and the hard drive has been working perfectly ever since the low level format. Strange thing though, the system has 640 KB of RAM, but I'm having a hard time loading certain games. Round 42 doesn't even load, and Wheel of Fortune gives me the error "Program too big to fit in memory". Kinda strange considering the entire program is only 300 something K. Any ideas?

Edit: Just realized there was a tech support forum, forgive me for posting this in the wrong area.

 

[Chuck(G)]

No problem--sometimes the "Program too big to fit into memory" message is because the file is corrupted. EXE files are a little different from COM files--a COM file is pretty much a straight image of the program in memory. DOS reads in a COM file and transfers control to the beginning. An EXE file, on the other hand, is a series of tables that tells the OS where to put things and how to adjust addresses.

Microsoft used to distribute a utility with their development tools called EXEHDR which would tell you what was in the EXE file headers. If you look around on the web, you might find a copy--it's not that there ever was any secret about EXE file structure.

As a side question, how much memory do you have available after loading your OS and drivers? That's the amount that determines what will load.

 

[m1k3e]

No problem--sometimes the "Program too big to fit into memory" message is because the file is corrupted. EXE files are a little different from COM files--a COM file is pretty much a straight image of the program in memory. DOS reads in a COM file and transfers control to the beginning. An EXE file, on the other hand, is a series of tables that tells the OS where to put things and how to adjust addresses.

Microsoft used to distribute a utility with their development tools called EXEHDR which would tell you what was in the EXE file headers. If you look around on the web, you might find a copy--it's not that there ever was any secret about EXE file structure.

As a side question, how much memory do you have available after loading your OS and drivers? That's the amount that determines what will load.

That makes a lot of sense actually considering I'm having problems using Laplink to transfer the files over in the first place. I'm using a parallel cable and I keep getting timeout errors. Even when the transfer is "100% errorless" I think I'm getting corrupt files. For example, I zipped up the files for Wheel of Fortune and sent the zip over. I couldn't unzip the file on the XT end because the zip was corrupted, even though the transfer was "errorless". I just ordered a serial cable, hopefully that works… Think this is the problem? Thanks a lot for your help!

 

[m1k3e]

Actually now that I mention it, I have what looks like an ISA I/O board with a serial port and a parallel port. One thing is strange, the serial port has a female style connection. Is this normal?

 

[Great Hierophant]

That is weird, the IBM standard calls for male serial ports and female parallel ports. I assume the parallel port is female.

 

[Chuck(G)]

If you've got an old copy (4.0 or earlier) of the Norton Utilities, there's a transfer program akin to Laplink that generally performs better than LL.

 

[RetroHacker_]

Actually now that I mention it, I have what looks like an ISA I/O board with a serial port and a parallel port. One thing is strange, the serial port has a female style connection. Is this normal?

Is this a nine pin port, per chance? That's probably a monochrome video card. A lot of mono cards included a parallel port as well, and I've seen systems that use CGA with a mono card installed solely for the parallel port.

-Ian

 

[per]

Actually now that I mention it, I have what looks like an ISA I/O board with a serial port and a parallel port. One thing is strange, the serial port has a female style connection. Is this normal?

How big is the board? if it reaches compleetely over the motherboard; it's most problably a MDA (monochrome display adapter) card.

Pictures?

 

[m1k3e]

How big is the board? if it reaches compleetely over the motherboard; it's most problably a MDA (monochrome display adapter) card.

Pictures?

I think that's exactly what it is. The video card that I took out was labelled STP. I think the port I thought was a serial port is the MDA output on a IBM MDA + printer port that was in there as well. I'll post pics of all the cards I have in the computer, as I'm a bit confused as to what all the ports are. I'll put them up soon as I'm back on the island. Thanks again to everyone for the help and all the suggestions!

 

[m1k3e]

Okay, so here's some pictures. I found out that the parallel port I was using was in fact on a MDA + Parallel card from IBM. I should have realized when the board was the same exact length and color as my IBM CGA board. Anyways, turns out that I bought the XT with two video cards installed. The second video card is made by STB. I'm guessing it is an MDA card because I plugged it into my 5151 and it outputted fine. Not sure why the previous owner installed a second MDA card, unless the STB card is not an MDA card (is that possible?). Secondly, I found another little port that I'm not sure what it is. I've attached images of both cards and their respective ports. Anybody have any idea of what they are?

Also I think I'm going to pick up an IBM serial + parallel card off eBay so I don't have to have two video cards in this thing. I saw a Texas Instruments one going for a bit less than the IBM one, shouldn't make any difference no? Anyways thanks for the help!

 

[m1k3e]

Few more pictures…

 

[RetroHacker_]

Your unknown card is a mouse interface card.

As for why there were two video cards in one system, the old MDA card was probably only being used for it's parallel port.

-Ian

 

[per]

Your unknown card is a mouse interface card.

As for why there were two video cards in one system, the old MDA card was probably only being used for it's parallel port.

-Ian

Or the other videocard was bougth and installed afterwards because the owner wanted expanded usage.

Regarding the STB video-card, I wonder if it is hercules compatible. In that cause, it can display 1-bit-per-pixel graphics, not just text. That's something the IBM MDA can't. It can also be something like a CGA card with autodetect on the monitor. In that cause, it might be able to display CGA on the IBM 5151 monitor (in grey[or green]scale of course).

 

[Chuck(G)]

The funny mini-DIN is for a bus mouse.

Without knowing (or seeing the entire card) the model of the STB card, you could have either a CGA or EGA card.

Edit Looks like others came to the same conclusion about the mouse card.

My guess is that the STB is a mono graphics or even MCGA card of some sort, but that's not the whole story--there are too many resistors at the DA-9 for that. I'll check my old catalogs and see what I come up with.

 

[Fallo]

I see that you did attach a photo of the STB card. My guess is an EGA card, judging from the number of resistors at the DA-9 connector.

It might be similar to the Compaq VDU, meaning that it's a CGA card, but outputs an MDA signal (ie. 18 Khz). It can't be an EGA card set to monochrome, because it wouldn't work in the same computer as an MDA card (EGA set to monochrome uses B000h for text mode and ports 3B0h-3BFh).

 

[per]

It can't be an EGA card set to monochrome, because it wouldn't work in the same computer as an MDA card (EGA set to monochrome uses B000h for text mode and ports 3B0h-3BFh).

Don't be to sure about that. Maybe it can be configured to emulate CGA (for output to a Monochrome monitor), and to emulate the CGA memory addressing in addition to that. Then it will work in a setup containing a MDA card.

I think you're guaranteed that it will support Hercules emulation with the rigth settings.