Bull Micral 45 - revival

[fneck]

It shows that you have 3072k of external RAM, but how much of it have you installed? 4x1Mb?
I've installed 6Mb but can't properly configure them. I am not sure that my board uses more than 640k since it's not shown anywhere.

Yes, I have 4 MB installed. I configured 3072 K because that's what the screen shows at the boot level. But I noticed something strange, I am systematically obliged to run the setup program twice so that the memory is taken into account. After it's good.

It is true that on your boot screen we do not see the extended memory. Are you sure you do not have only 256 KB SIMMs?

[Lenord]

Yes, I couldn't get anything over 640k to show on boot screen. All my switches and jumpers are the same as yours.
Originally, there were 6x SIMMs (4x256 + 2x64) and I've installed there 4x1Mb kit (i have 4 different kits like this, all of them tested to work ok in 486).
I thought that just this info might be hidden in my BIOS revision, but now i don't think so.
If i configure the PC as 3072k with diskette, memory size error still persists after reboot.
How to check the size of extended RAM?

I've tried some testing software (like Landmark speedtest) and it shows ~8MHz CPU frequency.

[fneck]

Before any software can tell the amount of RAM it is necessary that the BIOS of the machine detects it correctly.
This is the second count line on this screenshot:


You can try to put only two 1 MB SIMM to see. Then two others...
If it's not good, check that the supports and SIMM's contacts are clean. You can use an ink eraser to clean the memory contacts.

[Lenord]

You can try to put only two 1 MB SIMM to see. Then two others...
If it's not good, check that the supports and SIMM's contacts are clean. You can use an ink eraser to clean the memory contacts.

Ok, i will try that. I suspect plastic clips holding those simms, some of mine were broken off (one side).

[Totor le Butor]

Don't forget that most of earlier PC (8088, 286 and first 386) tests only the standard base memory, 640K, some other can test 1MO (640 + extended 384k) but it's depend of BIOS revision.
To have full access to memory above 1MO or 640K you must put EMS or XMS driver in config.sys. Whitout these drivers your old PC is blind to memory above 640K.

[fneck]

How to check the size of extended RAM?

Otherwise you can simply see the amount of memory with the Md-Dos MEM command (from Ms-Dos 4 and above).

@Totor, Your remark is true for the additional memory card but generally when the memory is on the motherboard, she's counted at boot time. In this case I see it well. After for use it you need additionnal drivers such as HIMEM.SYS from Ms-Dos.

[fneck]

I found online how to dump the BIOS with the DEBUG command here: http://mess.redump.net/dumping/dump_bios_using_debug

it's easy enough, above the syntax (you should only type what is next to a "-" or ":")

Code : Tout sélectionner

C:\> DEBUG
-N MYF000.BIN
-R BX
BX 0000
:0000
-R CX
CX 0000
:8000
-M F000:0 8000 0100
-W 0100
-N MYF800.BIN
-M F800:0 8000 0100
-W 0100
-Q

Thus we obtain two files of 32 Ko which correspond to the address F000-F7FF and F800-FFFF (not the two Eprom of the motherboard).

Then I quickly compared our two ROMs, there are many similarities.
What's fun, yours is in v2.0 while mine is in v1.2 and yet mine is more recent

[Lenord]

Well, i've tried to do everything and got small progress.

First of all, your fixed config image works fine, I've resized it for 1.44Mb floppy because I expect problems with loading 360k images in 1.44Mb floppy drive.

Basic part:
1. some of my 30-pin modules don't work here. In any combinations. Doesn't matter, if they are old or not.
For instance, 9-chip 120ns modules from ATARI or 3-chips 70ns modules aren't working there but they are tested in 486.
2. banks can't be filled from the end. System doesn't start with 1st bank empty.
3. configuration diskette can't do anything with external memory size on boot. It just compares programmed size with actual and gives out error if they aren't same.
4. 4Mb modules don't work there in any bank.
5. cleaning contacts and/or pulling modules towards slot contacts don't change anything
6. I've tried to find any PCB damage near the memory slots and couldn't find anything.

Further investigation:
7. If any two modules are installed (2x256k, 2x1M) in the first bank, system will only see 512k (not 640!) of Base and 0 External RAM. If I install just 2x64k modules there, it counts 128k but can't complete this test.

8. If only 4x modules are installed (any - 4x256k, 4x1M) in the first two banks, system will see 640k of Base but 0 External RAM. If 2x256k and 2x64k are installed, this is also true.
9. If any 4x modules are installed in two first banks and 2x more are installed in the last bank, system will see 640k of Base and 512k of External RAM. This size does works and completes EMT program test in DOS without any errors. I can't get any more, i.e. i should get 5000k+ as extended RAM with 6x1M simms, but 512k is the best result I could get. In addition, this size is minimal allowed by configuration diskette.


DOS problems:
10. When I were looking for DOS with HIMEM driver, I got troubles with DOS. Most of the versions don't work, they just stop at the stage of booting from floppy. For example, this DOS 6.22 with Norton doesn't work
http://old-dos.ru/dl.php?id=10158
and even dos 3.3 doesn't work.
http://old-dos.ru/dl.php?id=17329
I couldn't succeed with the one i used on 486,
http://comp.site3k.ru/include/_download ... otdisk.exe
Please try to test these 3 mentioned images on your system.

Most of 1.44 images in this list don't work,
http://old-dos.ru/index.php?page=files& ... ow&id=5526
I succeeded with 6.22 version named "dos62.bif" there. But this floppy has no free space.
I tried to dump my bios via DEBUG command and it worked out but didn't fit.

Don't forget that most of earlier PC (8088, 286 and first 386) tests only the standard base memory, 640K, some other can test 1MO (640 + extended 384k) but it's depend of BIOS revision.

At least, now we know that it's not my bios hiding string with tests of external memory size but something else.
Also, that's not caused by bad simm module or loose contact.

Now I am also using 9-chip SIMMs too and I don't think it could be the problem.
Also, it's very suspicious that originally with this board i got 4x256k and 2x64k RAM, which gives..... 640+512k exactly.

Then I quickly compared our two ROMs, there are many similarities.
What's fun, yours is in v2.0 while mine is in v1.2 and yet mine is more recent

Very strange, but if it's more recent, maybe your version can cope with more than 1Mb that can't mine.
Anyway, I need your images or Modbin dump, but

Thus we obtain two files of 32 Ko which correspond to the two Eprom of the motherboard.

I am not sure that these images do compare with real data and thus will work. If i get the flasher and UV lamp, i will try programming some other chips with your images, but if you have flasher, their direct dump might be rather more useful.

There also exist two handy utilities, both can dump the bios and divide it onto two parts,
1. BIOSUTIL
https://www.pcorner.com/list/DIAGS/BIOSUTIL.ZIP/INFO/
https://yadi.sk/d/kfDr0nce3CKpgE
2. ROMDEBUG
http://ftp.mpoli.fi/pub/hardware/ROM/OTHER/
https://yadi.sk/d/zdSDiLbW3CKpfD

I used first one, there is my bios image and its odd/even parts
https://drive.google.com/file/d/1hv63T9 ... sp=sharing
It seems that videobios of EGA card is located in the main BIOS of the motherboard.


Could you answer,
Is your CPU quite hot? Can you hold a bare finger for more than 5 seconds?
Please run Landmark test and check, what's speed of your CPU? http://old-dos.ru/dl.php?id=6551
Are you getting your results (with 3072k of extended RAM) with VGA videocard and #5 enabled on SW1 panel?

[Lenord]

I've got 2048k of extended RAM.
SW1 configuration influence on that.
№1=OFF allows to get 512kb of ext. RAM and no more.
№2=ON gives 2048kb of ext. RAM.

But this works ONLY if last bank is populated(i.e. all 6x SIMMs installed). If there aren't any SIMMs (i.e. just 4x or 2x SIMMs installed) or №1 is set "enabled", then I am not getting any extended RAM on start at all.I couldn't get more that this quantity with other settings.

To sum up, for some reason first SIMM bank gives only 512k, second gives remaining 128k of main memory and only the last one gives extended memory.I've replaced 4x1M memory in first 2 banks with 2x256k and 2x64k and it's the same. If 2x64k are installed at the very first bank (and 2x256k at the second) it doesn't count main memory, so the first bank should be populated with at least 2x256k modules.

Also, these SW1 settings are contrary to yours.

[fneck]

OK, I will try to answer all your questions. For memory, that 4Mo modules do not work is normal, just as the banks must be filled in order starting from the first one too. Then you do not specify but you have to put the same ram two by two, OK? I also saw that the management of the memory was particular, without the documentation I fear that one will not find. I hesitate on my side to touch switches without knowing what they do exactly.

Is your CPU quite hot? Can you hold a bare finger for more than 5 seconds?

It is hot but I can touch le CPU more than 5 second... I measured with a kitchen laser thermometer, it is at 45 ° C in the center with a hot spot near 60 ° C on one of the edges.

Please run Landmark test and check, what's speed of your CPU?

Otherwise I found that the speed was switchable by software. And the right LED on the front indicates this high or low speed.


Download this archive, it is not intended for the BM45 but it still works. On the first floppy disk you will find a SPEED.EXE that uses "SPEED /+" or "/-" and changes the speed. But, at each restart, it repsasse in high speed. The second disk is the setup but it does not work at home, he says it's not the right machine.

Are you getting your results (with 3072k of extended RAM) with VGA videocard and #5 enabled on SW1 panel?

Yes.

[fneck]

I have the impression that for the amount of memory, according to what you tell me, it is necessary both to inform the SETUP but also the switches on the motherboard...

[edit] I confirm that SW1-1 has an influence on the memory. Without changing my 4 MB installed, the computer does not see more than 2 MB (640 + 1024) if I put this switch on 0.

[Lenord]

It is hot but I can touch le CPU more than 5 second... I measured with a kitchen laser thermometer, it is at 45 ° C in the center with a hot spot near 60 ° C on one of the edges.

You have nice equipment)
I don't have any laser thermometer, but have thermocouple which gives ~59 degrees at the center. Yours is definitely not so hot, I agree.

Otherwise I found that the speed was switchable by software.

I've downloaded this image, thank you.
I couldn't boot from that floppy, but in other DOS this SPEED.EXE changes low and high CPU modes.
Nevertheless I can't see any difference, it's always 8MHz and performance rating remains the same.
Up to this moment I've tried: Landmark test, System checker test, Maxspeed test.

And the right LED on the front indicates this high or low speed.

On my system, this "Turbo"LED is always off, it doesn't react onto software switching, jumper changing and switch configuration.

But, at each restart, it repsasse in high speed. The second disk is the setup but it does not work at home, he says it's not the right machine.

At each restart this LED is inactive. I tried connecting it vice-versa and replace with other LEDs but I couldn't see any light (like with power LED).

Then you do not specify but you have to put the same ram two by two, OK?

I have 4+ different 4x1Mb 30-pin kits. I've tried all of them, installed 4 identical and just pairs. I think, that's not memory fail.
What i know is that with your settings (pictured) it doesn't recognise any ext. RAM and it doesn't matter which modules are in the first 2 banks.

I also saw that the management of the memory was particular, without the documentation I fear that one will not find. I hesitate on my side to touch switches without knowing what they do exactly.

Ok, i will be a pioneer there, for me it's easier as I don't have any case

I have the impression that for the amount of memory, according to what you tell me, it is necessary both to inform the SETUP but also the switches on the motherboard...

Yes, you're right, some software stops booting if the PC loses that saved configs. But now, after setup, I don't get any errors during boot.

I confirm that SW1-1 has an influence on the memory. Without changing my 4 MB installed, the computer does not see more than 2 MB (640 + 1024) if I put this switch on 0.

0 means OFF or ON? And you're getting 3072k in 4 slots with SW1 settings pictured above?
Really strange behavior.

Could you dump your BIOS image? It's more convenient to use BIOSUTIL I've provided earlier.

[fneck]

I have the BIOS files done previously with DEBUG, there are here https://software.system-cfg.com/bios/bull/

Ok, When I say 0 it means "open".

I have more and more the impression that your mainboard has a real problem ...

[Lenord]

I have more and more the impression that your mainboard has a real problem ...

Maybe this. I will try to borrow another CPU and check again.
The second opportunity is to try your BIOS.

[fneck]

I'm thinking of something about your reading problems that you encounter. Are you careful about the hole present or not on the 720 Ko or 1.44 Mo disk?