The following are the known patches for DOUBLEDOS version 4.0. You
should always work with a copy of the file and not the original. The
DEBUG program should be available via path or be called explicitly.
The patch dialog would be something like the following:

C:\dirname\>DEBUG DOUBLED2.PGM (may also be called DOUBLEDO.PGM)
- enter changes as specified in patch
-W
writing xxxx bytes
-Q

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Revert to old version 'V' of DoubleDOS
COPY A:\DBLDVPGM.DRV C:\dirname\DOUBLED2.PGM (or DOUBLEDO.PGM)
note: this is not a permanent change. re-installing the program will
restore it to version 4.0

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Hewlett Packard Vectra 1/14/87
-E 85D5 F5 (old value BA)
note: will not work with International Quartz laptop after this patch.

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very slow printing w/clock or interrupt
-E 116 EA 83 (old values 6E B0)
-E 24A9 21 90 ( " " E8 BD)
note: only use with clock or interrupt when very slow printing occurs.

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IBM DOS 3.3 4/24/87
-E 2130 20 (old value 10)
-E 878C C0 A1 ( " " 41 81)
-E 8B7D 03 50 ( " " 6C 4C)
-E 9487 7F FF B7 6E 20 80 C2 ( " " A7 E0 C5 32 0B 33 FF)
note: will not work with any other operating system after this patch.

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Columbia DOS 3.20
-E 8B7D CE (old value 6C)
note: will not work with any other operating system after this patch.

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Drives with volumes larger than 32 megabytes
-E 4E3A 5F B8 (old values 5C F8)

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COMx=BOTTOM
-E 1237 1F (old value 1B)
-E 1256 1F ( " " 1B)
note: caused junk to be written to random locations in memory.

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Sanyo MBC-990 7/2/87
-E 99DB 12 09 (old values 8E B4)
note: problem is due to a hardware bug. this patch removes an I/O
word read instruction that fails on the Sanyo.

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IBM PS/2 model 30 4/28/87
-E 9075 BA 42 21 (old values 47 FE 45)
-E 9829 09 71 ( " " E0 F8)
-E 982E AF 3A 58 A9 (" " 47 87 3D D0)
note: since this machine requires DOS 3.3, the patch for that will
also be needed.

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REMM.SYS and other expanded ram boards 8/4/87
-E 1AA1 83 E3 E0 38 D2 9C A0 56 0D
(old values 23 19 E8C6 3A 81 B8 01 93)
-E 2366 63 81 95 43 10 AF 12 FD
(old values 47 81 FC D0 31 2E 7C 96)
note: the symptom is that DoubleDOS will work correctly without the
expanded driver present, but will fail with it installed.

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