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XT clone built from ebay components

SomeGuy said:
mikey99, do you happen to know if your BIOS is also the same "Special Integrated Designs Co" OEM?

......
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I'm fairly certain that mine contains a standard BIOS, probably an ERSO. I haven't booted this system in awhile.
 
Making progress... I'm at a point where this XT clone _almost_ boots. I had the wrong bios in the XT-CF adapter, and that was preventing the board from booting, even though it worked in 3/486-class machines. So I compiled a new bios from svn, but then I was still left with the problem that I have no way to transfer it to floppy for flashing. But thank God for socketed chips, I pulled the flash chip from the XT-CF adapter and flashed it in my eprom programmer, after first configuring the bios with xtidecfg in DosBox on my laptop. :) And of course at the first attempt I configured it wrong, by selecting "XT-IDE rev.2" as adapter where I should have selected XTCF-PIO instead... Anyway, I got it configured correctly, flashed, verified that it boots correctly in my 386, then installed in the XT.

It doesn't stop it from booting anymore, the bios at 0x8b00 kicks in correctly, it recognizes the attached Hitachi microdrive, tries to boot.... then stops with "unrecognized partition table" error. The microdrive has on it a 2GB FAT16 partition with DOS 6.20, and it is recognized and boots correctly with the new bios on a 386. I thought that it would work on the XT also, but apparently it doesn't. So what kind of partition table does it expect? FAT12?


(and another thing - before this I tried to see if I can have it boot from a 720K floppy - but none of my 3.5"/1.44M floppies would allow to be formatted as 720K, and I don't have any DD floppies. Bummer.)

FWIW this is the exact adapter I'm using: http://www.lo-tech.co.uk/wiki/Lo-tech_ISA_CompactFlash_Adapter_revision_2 (version 2, not the newer 2b)
 
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jh1523 said:
(and another thing - before this I tried to see if I can have it boot from a 720K floppy - but none of my 3.5"/1.44M floppies would allow to be formatted as 720K, and I don't have any DD floppies. Bummer.)
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Have you got the hole with out the write protect slider covered up? What are you using to try and format them?
 
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Ohh!!! The hole! The frickin' hole!! I completely forgot about the hole. To be honest, it's been at least a decade since I last thought about that damn hole.

One bit of sticky tape later, problem solved.

And... It's alive! Well, sorta. It booted from floppy, I fdisk'ed the microdrive and it only allows me to use 39.19MB of it. Not sure where that limitation comes from, must be something in the xt universal bios or the way I configured it. I can read and write from/to the microdrive.

But it doesn't boot from it even with the OS properly transferred. After the boot menu where I select which drive I want to boot from, if I choose the floppy it boots. If I choose the HDD, it hangs at "booting C>>C"
 
jh1523 said:
But it doesn't boot from it even with the OS properly transferred. After the boot menu where I select which drive I want to boot from, if I choose the floppy it boots. If I choose the HDD, it hangs at "booting C>>C"
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Your microdrive may have a non-standard boot sector.
Try booting from a DOS boot floppy (must be DOS version 5 or later) then issue the command: FDISK /MBR
 
I tried that too yesterday, didn't work. And where did the 39.19MB limit come from? That's what format.com reports after the disk was freshly fdisked with the option to use all the space for the primary DOS partition (MSDOS 6.20)

I ended up blanking the whole microdrive (writing zeroes to it in Linux) then redoing fdisk and format; still only 39.19MB usable, but now it boots.

Now onto digging up that stack of memory cards I used to have and see which one can expand this bad boy to 1M. :)
 
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I've abandoned the microdrive because it acts weirdly. I think it may not be properly supported by the XTIDE universal BIOS. Instead I dug out an old 64MB CF card, which this system can format to full capacity and boots fine.

I've also found my old Rampage card http://www.uncreativelabs.de/th99/i/A-B/51238.htm and installed it using REMM v.4.70. It creates an EMS page frame OK, but what I'd really want is to configure some of its memory as UMBs. Except that I can't seem to remember how to do that. :(

Any help?
 
Stone said:
USE!UMBS.SYS is an Upper Memory Block Manager for PC/XT/ATs. That should work nicely.
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Hmm. Does it use the memory from the expanded memory card to create UMBs though? I thought I needed first to have some of the memory from the card mapped in the UMB area, and for that I need to pass parameters to REMM.SYS (so it creates more than just four 16KB pages), except I don't remember what those were. The motherboard itself has no memory above 640KB.
 
Well I've tried a few things that I remembered with REMM.SYS, but I didn't really get any usable result. I can move the frame page around with /S=xxxx, but the /L=xxxx-yyyy option to create extra memory doesn't seem to do anything. After using it I tried several of those programs that are supposed to identify UMBs, and none of them can find any RAM in the ranges I specify. Was the /L option deprecated at some point? What version of REMM.SYS do I need to use to make this work?

(edit) So I've tried multiple versions of REMM.SYS including the oldest I could find, 3.10 - they all accept the /L parameter, but none of them seems to create any additional UMBs, at least none that other programs can find or use.
It seems that I'm stuck with 640KB + EMS until my lo-tech 1M board PCB arrives from England, and components via slowboat from China, and I have some time again to put it together and test...
I don't really need EMS, but I could use UMBs to load drivers etc. high.
 
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You should try the USE!UMBS.SYS program. It comes with a utility that will let you know immediately if you can gain anything from it.
 
Stone said:
You should try the USE!UMBS.SYS program. It comes with a utility that will let you know immediately if you can gain anything from it.
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I did. It doesn't find any usable UMBs. It's one of the programs that I mentioned in my earlier post that "can't find or use" upper memory. Others that I've tried, also without success, were Hiram.exe and one called The Last Byte.
 
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I remember having a similar problem with REMM.SYS. I think it's the later versions that support LIM4.0 that don't work very well. I can't remember which version I eventually settled on, but I know it was not v4.70. It was either a very late v3.x or an earlier version of v4.x

I'll be on the road for the next month, so I unfortunately I can't check it for you.
 
Anonymous Coward said:
I remember having a similar problem with REMM.SYS. I think it's the later versions that support LIM4.0 that don't work very well. I can't remember which version I eventually settled on, but I know it was not v4.70. It was either a very late v3.x or an earlier version of v4.x

I'll be on the road for the next month, so I unfortunately I can't check it for you.
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But did you eventually get it to work? If so, I can keep checking. I have found many versions of REMM, from 3.10 to 4.70 - about 6 or 7 of them, but haven't checked them all.
 
jh1523 said:
I've abandoned the microdrive because it acts weirdly. I think it may not be properly supported by the XTIDE universal BIOS. Instead I dug out an old 64MB CF card, which this system can format to full capacity and boots fine.
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The 6 GB Hitachi microdrives are definitely supported. I know Tomi (aitotat) use them and he even recommends using them in the manual.

Did you make the BIOS from the latest revision? What build options did you use when building it? What (if any) configuration changes did you do with XTIDECFG?
 
Krille said:
The 6 GB Hitachi microdrives are definitely supported. I know Tomi (aitotat) use them and he even recommends using them in the manual.

Did you make the BIOS from the latest revision? What build options did you use when building it? What (if any) configuration changes did you do with XTIDECFG?
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I checked out the latest SVN and used mingw32 to compile it. Here are the options I used:
Code: 
DEFINES_XTCUSTOM = MODULE_8BIT_IDE MODULE_8BIT_IDE_ADVANCED MODULE_COMPATIBLE_TABLES MODULE_BOOT_MENU MODULE_EBIOS MODULE_IRQ MODULE_STRINGS_COMPRESSED ELIMINATE_CGA_SNOW RESERVE_DIAGNOSTIC_CYLINDER MODULE_POWER_MANAGEMENT

At configuration time, all I did is change the type of controller to what I have (XTCF-PIO), nothing else.


As to REMM versions, I tried the following: 3.10, 3.30, 4.10, 4.20, 4.30, 4.31, 4.40, 4.41, 4.70. None of them will allow me to create extra RAM with the /L parameter. A couple of them (4.10 and 4.20) don't even accept the /L parameter at all, and generate an error and refuse to load if /L is specified.
 
Another bit of work that I've done on this computer. Since I've got a XT-CF card in it anyway, and that has on-board flash ROM, which I'm using only 8KB out of 64KB, I thought I might add something else in there. Such as support for HD floppies. :)

I appended to the XT-IDE bios the firmware from a 8-bit FDD controller from here: http://www.minuszerodegrees.net/rom/rom.htm specifically I used the KW-530D image (pretty much at random from the many FDD roms on that page) and flashed the bunch into the XT-CF ROM.

Now this XT not only supports HD floppies, but also can boot from them. :)

Now, what to do with the remaining 48KB...

Trixter said:
Have you tried QRAM?
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I have not tried QRAM, but I don't expect that it will find usable RAM where there is none. :)
 
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I have not tried QRAM, but I don't expect that it will find usable RAM where there is none. :)
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Maybe I misread the above info, but if you have a hardware page frame, QRAM will give you UMBs. I'm using it on an 8088 and I have both UMBs and EMM with my Intel Aboveboard (and I am NOT remapping the hardware EMS into the lower 640KB).
 
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