• Please review our updated Terms and Rules here

My 286 clone build

D

dieymir

Experienced Member
Joined
Jan 11, 2017
Messages
245
Location
Spain
Finally I will give my 286 a proper house. This one:

caja.jpg

I'm trying to identify the homeless in this thread: http://www.vcfed.org/forum/showthread.php?56330-Identify-this-286-board

The specs:
* 286@12Mhz NMOS Intel processor
* 2MB of RAM (1MB in 80ns DIPs and another one in 256KB 70ns SIMMs). An AMD CMOS 287@10Mhz
* SUNTAC chipset. AFAIK this chipset can work in EMS or Extended memory memory but you cannot have both types of memory. I've configured mine in EMS mode which IMHO it's much more useful on a 286.
* Acer M5105 super I/O chip. It has a 2 COM ports, 1 LPT, 1 floppy and 1 IDE.

These are the cards:
IMG_20170219_100436.jpg

For the OSs I intend to multiboot PC DOS, MS-DOS 3.30 and an DR DOS 3.40 or older if I can find it

I intend to show my progress with this build, get new ideas and ask questions in this thread.

Thanks a lot to everybody
 
Last edited:
You probably want at least some Extended memory, because that supplies the HMA (so you can load DOS high and get more conventional memory free) and HIMEM.SYS provides XMS services from Extended memory as well, which I think is more widely used than EMS.

The two 286 boards I have tested that have hardware EMS all allow you to specify the amount of memory to dedicate to EMS, leaving the rest as Extended. I typically only allocate a small amount (say 384kB) because the only use of it I know of is Monster Bash for sound effects. I think every other game I play that needs a lot of memory supports XMS. Bear in mind that you have to load a driver in CONFIG.SYS before the emulated EMS will work - the driver translates EMS API calls from programs into chipset register writes to make the hardware EMS actually work. Without the driver the system will think you have no EMS. If you can find an EMS driver that works with your board's chipset, that might give you some more information to help identify it.

1MB SIMMs seem plentiful on eBay (at least here in Australia) so you could always upgrade it to 4MB total RAM too.
 
DOS 3.30 has partition size limit of 32 MB, and if you're going to use an IDE drive, it's likely to be much bigger.
DR DOS 3.40 should be OK, though.
You can also try Compaq DOS 3.31, if you don't want any modern DOS.
 
Malvineous said:
You probably want at least some Extended memory, because that supplies the HMA (so you can load DOS high and get more conventional memory free) and HIMEM.SYS provides XMS services from Extended memory as well, which I think is more widely used than EMS.

The two 286 boards I have tested that have hardware EMS all allow you to specify the amount of memory to dedicate to EMS, leaving the rest as Extended. I typically only allocate a small amount (say 384kB) because the only use of it I know of is Monster Bash for sound effects. I think every other game I play that needs a lot of memory supports XMS. Bear in mind that you have to load a driver in CONFIG.SYS before the emulated EMS will work - the driver translates EMS API calls from programs into chipset register writes to make the hardware EMS actually work. Without the driver the system will think you have no EMS. If you can find an EMS driver that works with your board's chipset, that might give you some more information to help identify it.

1MB SIMMs seem plentiful on eBay (at least here in Australia) so you could always upgrade it to 4MB total RAM too.
Click to expand...

Unfortunately this is not the case with this chipset. It's all or nothing. I do not intend to use any dos version higher that 3.3x so it's not a big problem. I have the EMS driver, in fact I'm using QRAM to get 32KB of UMBs using EMS 4.0. As a bonus QRAM provides memory through XMS API so I'm loading 4DOS high too. With all these tricks I was able to get 590KB of memory free (cache, mouse driver, 4DOS, keybsp and DOS resources loaded high). I intend to post my CONFIG.SYS and AUTOEXEC.BAT for your reference.
 
Xacalite said:
DOS 3.30 has partition size limit of 32 MB, and if you're going to use an IDE drive, it's likely to be much bigger.
DR DOS 3.40 should be OK, though.
You can also try Compaq DOS 3.31, if you don't want any modern DOS.
Click to expand...
No problem with that. I have a Seagate ST3120A (106MB) drive but, unfortunately, it has lot of bad sectors :( so I'm looking for a replacement not bigger than 130MB. I'm also looking for DR DOS versions older than 3.4x to keep everything in the 3.3x range ;) but seems that it'll be easier to find a hen with teeth.
 
dieymir said:
I'm also looking for DR DOS versions older than 3.4x to keep everything in the 3.3x range ;) but seems that it'll be easier to find a hen with teeth.
Click to expand...

Near as I can tell this is the copy of DR-DOS 3.31 thats been floating around the net for a while (exact same file size posted in several different sources). Not 100% its accurate, but check it out.

View attachment drdos331.zip
 
EMDarrow said:
Near as I can tell this is the copy of DR-DOS 3.31 thats been floating around the net for a while (exact same file size posted in several different sources). Not 100% its accurate, but check it out.

View attachment 36505
Click to expand...

I know about it. Unfortunately this copy is corrupt and does not boot. Seems that those kernel files were uploaded to the Caldera FTP site in ASCII mode :(
 
As promised here are the contents of the CONFIG.SYS and AUTOEXEC.BAT files

Code: 
C:\>TYPE CONFIG.SYS
DEVICE=D:\DRIVERS\MMP16ABO\DRIVERS\EEPROM.SYS /88BC0001
DEVICE=D:\DRIVERS\SUNTAC.SYS /R:0 /R:1 /R:B
DEVICE=C:\QRAM\QRAM.SYS R:1 NOSH
BUFFERS=1
FILES=8
FCBS=1,0
LASTDRIVE=D
STACKS=0,0
COUNTRY=034,437,C:\DOS\COUNTRY.SYS
SHELL=C:\4DOS\4DOS.COM C:\4DOS /P

Code: 
C:\>TYPE AUTOEXEC.BAT
@ECHO OFF
C:\QRAM\LOADHI /R:1 C:\QRAM\BUFFERS=5
C:\QRAM\LOADHI /R:1 C:\QRAM\FILES=20
C:\QRAM\LOADHI /R:1 C:\QRAM\FCBS=4
C:\QRAM\LOADHI /R:1 C:\QRAM\LASTDRIV=Z
SET GALAXY=A220 I5 D1 K10 P530 T6
SET BLASTER=A220 I5 D1 T4
SET SOUND=D:\DRIVERS\MMP16ABO
SET PROMPT=$P$G
SET TEMP=C:\DOS\TMP
SET TMP=%TEMP%
SET PATH=C:\4DOS;D:\UTIL;D:\NU;D:\PCTOOLS;C:\DOS;
C:\QRAM\LOADHI /R:1  C:\EMMCACHE\EMC110.COM 40
C:\QRAM\LOADHI /R:1  C:\DOS\KEYB SP,437,C:\DOS\KEYBOARD.SYS
D:\DRIVERS\MMP16ABO\UTILITY\VOLSET /V:14 /X:14 /F:14 /C:14 /L:14 /M:0 /R:M
D:\DRIVERS\MMP16ABO\UTILITY\AZCAL
VER
 
I do not have much time those days so progress is slow. Here are some performance results

NI 4.5 SI:
IMG_20170225_224617.jpg

and Landmark v6.0 (I'm sorry for the quality of this I took the photo with my mobile phone and the CRT flickering is very obvious):
IMG_20170302_154606.jpg

as you can see the VGA Landmark figures are dismal. Not sure about the CPU ones Are those figures OK for a 12Mhz 286 with 0 WS and a 10Mhz FPU?

Soon I'll upload more photos of the assembled system (I'm still cleaing the case front bezel) and ask some questions.
 
Last edited:
Is this intended for a speaker?

IMG_20170303_202449.jpg

it has a diameter of 2.5cm. (1") Is this supposed to be a standard size? I was looking in my parts bin and did not find any speaker that fits (too small or too large).
 
I have seen some smaller piezoelectric speakers that were about 1" in diameter with a tab that matches the slot which might perfectly fit in that space.
 
I've got one or two "large magnet" small speakers. They weren't that uncommon. Worst case, you can use a standard speaker and slip a length of vinyl tubing over the magnet to make it bigger.
 
Stone said:
While it looks like a standard speaker bracket the diameter of the PC/XT speaker is 7/8" or ~ 2.3cm.
Click to expand...
I didn't know that. Only 2mm ... I'll measure it again more carefully (with a better tool) and see.
 
I just took a more precise measurement:

inside diameter = 21.5 mm

outside diameter = 24.5 mm

Actually, it's only the ID that matters.
 
You must log in or register to reply here.
Back
Top