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Thread: PC-DOS 3.2 for 5150

  1. #91
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    Quote Originally Posted by Trixter View Post
    Agreed. That was quite bananas.
    Apparently some people are *very* passionate when it comes to command-line syntax for taking a disk directory.
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  2. #92
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    Quote Originally Posted by dreNorteR View Post
    The idea is to run this from plain DOS without any drivers when you need the extra memory.
    I always need the extra memory.

    I recently tried to install OS/2 1.3 on a system with only 1 MB of extended memory (NEAT chipset, 2 MB total but 640-1024K shadowed). The installer crashed because there wasn't enough memory. Wrote a small program to enable RAM at A000-B7FF and reboot from the installation disk, and it worked. Not very usable with this little memory though
    If you have to jump through hoops to install something, it's generally not worth attempting to run that something once installed.
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  3. #93

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    Quote Originally Posted by Eudimorphodon View Post
    I assume that's the Lo-Tech 2MB EMS card? If it is and you want to test a random thing some joker on the internet came up with I wrote a little point-enabler dingus, "ems2umb.exe" to set up a card compatible with the LTEMMS card to give you 64k of upper memory space without having to load the resident driver. The driver as compiled will only work if the I/O of the card is set to the default 260h.

    Anyway, using this lets you use USE!UMB.SYS to do upper memory stuff with MS-DOS 5 or later while saving the ~5k or so the EMS driver takes up. Obviously you don't get to use EMS when using it for this.
    I tested your tool on my 5150. When running it from the command line, it works fine (clean boot from PC-DOS 3.2 system disk), but when I tried to load it as a device driver in my CONFIG.SYS it broke the console. The only line in the config was DEVICE=C:\EMS\EMS2UMB.SYS and it printed it's sign on text, but then DOS printed the error "bad or missing CON" and stopped responding to keyboard input.

  4. #94
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    Huh. I'll try it on some other DOS versions and see if I can replicate it. That code wrapper that lets the EXE run from config.sys is pretty much a black box to me.
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  5. #95

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    Quote Originally Posted by Eudimorphodon View Post
    Huh. I'll try it on some other DOS versions and see if I can replicate it. That code wrapper that lets the EXE run from config.sys is pretty much a black box to me.
    Try changing the MSB of your device attributes to a 0. That will change it to a block device instead of a character device

  6. #96
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    Quote Originally Posted by maxtherabbit View Post
    Try changing the MSB of your device attributes to a 0. That will change it to a block device instead of a character device
    I did some testing and the verdict seems to be that the EMS2UMB.EXE file works on DOS 3.3 or later, but I do indeed get that "Bad or missing CON" error on 3.21 or 2.11. I wonder what changed between 3.2 and 3.3. I also tested VGAFUDGE.EXE, which uses the same wrapper, on those OSes and it likewise trips the same problem. (It'd worked fine on 3.3, so I guess I assumed it was all good.)

    Just made your suggested change, changing the 1010000000000000b in the source to all zeros, and it seems to work! I was able to boot with ems2umb.exe in config.sys on DOS 2.11. (Which amusingly enough lets me run the 128k RAMDISK program that Tandy shipped with a rare 512k variant of their own memory card for EX/HXs on my haxxor'ed HX.) I'll make the same change to VGAFUDGE and ensure that works (and also works on 3.21) and update the github.
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  7. #97
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    Both binaries tested on Tandy DOS 3.21 and 2.11 (and PC-DOS 7 to ensure no breakage with higher OS-es), and updated source and binaries pushed to the github repository. Thank you for the help!

    (In particular it's probably good to make sure VGAFUDGE.EXE works on DOS 3.21; the UMB driver probably isn't super useful to people running less than DOS 5 except for a few weird cases but it's possible there's someone out there that wants to make a VGA card work right in a Tandy 1000 SX or TX with the original DOS that came with it.)
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  8. #98

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    Quote Originally Posted by Eudimorphodon View Post
    NICE!
    I just took a look at the datasheet for the RealTek 8019AS in my machine and it looks like the same trick might be possible. The bit in question refers to "Flash Memory", but all it does is gate whether the MEMW pin is enabled on the socket so I can't think of a reason why it wouldn't take an SRAM.
    And I can confirm that ... IT WORKS! I installed a SRAM chip in the ROM socket, and by enabling the "Flash write operation" I got 64K of RAM at the configured address! The socket in my card is hardwired for a 16K ROM, so I had to connect MEMW and the extra address bits with some wire and solder. It's a bit messy, but it works.

    Quote Originally Posted by Eudimorphodon View Post
    ... EDIT: On second thought, later in the manual it looks like "write enable" register might not have its state loaded from reading the EEPROM, enabling writes is something you'd have to do after power-on. So maybe if you wanted an SRAM in that socket you'd need to make a little device driver stub to throw the write enable at it before loading USE!UMB.SYS, which would sure be a pain. Not 100% sure, though...
    Actually, it is not that difficult. You only need a bunch of writes to the correct registers. I modified your EMS2UMB to enable "rom writes" and now I have 630K of free conventional memory, thanks to USE!UMB.SYS and DOSMAX. 621K if I load a packed driver and ethersrv. The code of the device driver stub is here: rtl2umb.zip

    Code:
    Modules using memory below 1Mb:
    
      Name           Total       =   Conventional   +   Upper Memory
      --------  ----------------   ----------------   ----------------
      SYSTEM       9,488    (9K)      9,440    (9K)         48    (0K)
      USE!UMBS       208    (0K)        208    (0K)          0    (0K)
      4DOS         4,896    (5K)        800    (1K)      4,096    (4K)
      DOSMAX         272    (0K)          0    (0K)        272    (0K)
      ANSI         3,600    (4K)          0    (0K)      3,600    (4K)
      SETVER         784    (1K)          0    (0K)        784    (1K)
      FILES        1,504    (1K)          0    (0K)      1,504    (1K)
      FCBS           272    (0K)          0    (0K)        272    (0K)
      BUFFERS      5,344    (5K)          0    (0K)      5,344    (5K)
      LASTDRIV     2,304    (2K)          0    (0K)      2,304    (2K)
      INSTALL        160    (0K)          0    (0K)        160    (0K)
      CTMOUSE      3,184    (3K)          0    (0K)      3,184    (3K)
      FREE       651,872  (637K)    644,896  (630K)      6,976    (7K)
    
    Memory summary:
    
      Type of Memory       Total    =     Used    +     Free
      ----------------  -----------   -----------   -----------
      Conventional          655,360        10,464       644,896
      Upper                  28,544        21,568         6,976
      Reserved              364,672       364,672             0
      Extended (XMS)              0             0             0
      ----------------  -----------   -----------   -----------
      Total memory        1,048,576       396,704       651,872
    
      Total under 1Mb       683,904        32,032       651,872
    
      Largest executable program size         644,880     (630K)
      Largest free upper memory block           6,976       (7K)

  9. #99

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    I don't follow - if you had to hardwire the MEMW strobe to the socket then what are the register writes actually doing? I thought the whole point of the register bit was to gate the memory write strobe

  10. #100
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    Quote Originally Posted by davide78 View Post
    And I can confirm that ... IT WORKS! I installed a SRAM chip in the ROM socket, and by enabling the "Flash write operation" I got 64K of RAM at the configured address! The socket in my card is hardwired for a 16K ROM, so I had to connect MEMW and the extra address bits with some wire and solder. It's a bit messy, but it works.

    Actually, it is not that difficult. You only need a bunch of writes to the correct registers. I modified your EMS2UMB to enable "rom writes" and now I have 630K of free conventional memory, thanks to USE!UMB.SYS and DOSMAX. 621K if I load a packed driver and ethersrv. The code of the device driver stub is here:...
    That's awesome! It occurred to me after I posted that comment about it being a pain to have to initialize the card registers before using it that the config.sys exe wrapper I used for my stuff would be a perfect fit for this problem, as long as programming the registers wasn't too much of a pain. I'm glad the code was useful start.

    (Is it okay if I mirror your source on the same repository as the others? If you have a github account I could give you submit privileges to the repository.)
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