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There is a lot of confusion over what DASDDRVR.SYS is, what it is used
for, which PS/2 models require it, and what exactly it fixes.
(July 1991 version is 3,068 bytes)
The following should dispel the mystery surrounding
DASDDRVR.SYS.
Model 85, 90, and 95 Systems
Don't Need DASDDRVR
DASDDRVR functions are performed by updated
Reference / Diagnostics diskettes, EPROM updates [T1 and
T2], and/or Flash updates.
What is it?
DASDDRVR.SYS (Direct Access Storage Device
Driver) is
a set of software patches that fix various BIOS bugs
common to several
PS/2 models. A common misconception is that
DASDDRVR.SYS is a set
of DOS patches; and additionally that it is not needed
with DOS 4.0x or
later; only V3.3. Both statements are
incorrect.
IBM could have chosen to replace thousands
of BIOS chips
on PS/2 motherboards, yet went with the software
approach. Why? A
program installs DASDDRVR.SYS on a PS/2 hard disk drive,
and adds a statement
to CONFIG.SYS. Then when the system is booted, the
BIOS patches overwrite
the BIOS code in memory (that was copied from the BIOS
ROM chips).
Not only does this give IBM and the user the flexibility
of later replacing
DASDDRVR.SYS with a newer version containing additional
BIOS patches, if
necessary; but it also eliminates the down time and
inconvenience that
would result from taking the system to an authorized
servicer to have the
BIOS ROM replaced.
Who needs it?
Originally, a few BIOS bugs were found
affecting several
PS/2 models. Two versions of DASDDRVR.SYS were
written,
one for MCA, and one for non-MCA PS/2s. But as
several more PS/2s were affected by these or newer
bugs, both versions of DASDDRVR.SYS were merged into
one.
DOS 3.3 and later users with specific
problems with a listed PS/2 should install DASDDRVR.SYS.
The install program determines which fixes apply to that
system. PS/2
models not on the list do not need DASDDRVR.SYS, and
will
not benefit by installing it.
Why isn't DASDDRVR.SYS
required on OS/2 or
AIX-based PS/2s?
Because these operating systems routinely
replace hardware BIOS code in memory with customized
software versions. They already contain the fixes
inherent in DASDDRVR.SYS.
What problems does it fix?
[July
1991]
There are twelve fixes that affect the specific
systems:
| Problems |
Systems Affected |
| 1)
Failures occur when
reading some 720K program floppies. |
8530-E01/E21; 8550-021; 8560-041/071;
8580-041/071 |
| 2)
Intermittent "Not Ready" or
"General failure" error messages when accessing
diskettes. |
8550-021; 8560-041/071; 8580-041/071 |
| 3) 3.5"
floppy format failures
when attempting to format multiple diskettes
consecutively. |
8550-021; 8560-041/071; 8580-041/071 |
| 4)
Combined 301 / 8502 errors at power on, or after
power interruption. |
8550-021; 8560-041/071 |
| 5) System
clock loses time (8550),
or combined 162 and 163 errors during system
POST (8560). |
8550-021; 8560-041/071. |
| 6) Unable
to install Power-on Password
program with DASDDRVR.SYS installed. |
8550-021; 8560-041/071; 8580-041/071 |
| 7) Device
attached to COM2, COM3,
or COM4 not detected. |
8530-E01/E21 |
| 8) Devices
that use interrupt request
level 2 (IRQ2) fail. |
8530-E01/E21 |
| 9) 3.5"
floppy format failures
when attempting to format >1 floppy. |
8570-Axx (all); 8580-Axx (all) |
| 10) System
performance degradation
from processor-intensive devices. |
8550-021/031/061; 8555-031/061; 8560-041/071 |
| 11) Error
in microcode routine
that enhances long-term reliability of 60/120MB
disk drives. |
8550-061; 8555-061; 8570-061/121/A61/A21;
8573-061/121 |
| 12) Time
& date errors occur
when resetting time & date. Intermittent
date changes can occur when
system is restarted by pressing C-A-D |
8530 (all) |
How do I get and install it?
Most versions of various MCA PS/2 RefDisks contain
some
version of DASDDRVR.SYS. (Non-Micro Channel PS/2
Model 30 286
provides DASDDRVR.SYS on the Setup Diskette) But
several versions of DASDDRVR.SYS have been released,
with different numbers of fixes, so it is important to
get the latest possible
version of the appropriate RefDisk. Depending on
the diskette version, there may be additional fixes in a
later version.
If you have the latest Reference Diskette,
use
it. If not, you may look for the PS/2 System
Update Diskette (P/N 04G3288. This diskette
contains a version of
DASDDRVR.SYS, but it is possible that by the time you
read this and order
it, a newer version may have been released on a new
Reference Diskette.
Still, a fairly recent version is better than an older
one you may have
on the Reference Diskette that came with the
system. If DASDDRVR.SYS
is already installed on a system, but you don't know
whether it is the
latest, just look at the file size. The current
version (as of July
1991) is 3,068 bytes).
Installation is a snap. Simply
insert the diskette
in the A: drive, and type: A:INSTALL from the
C> prompt. That's
all there is to it!
The install program copies the DASDDRVR.SYS file
to the hard
disk drive, and updates CONFIG.SYS to use it.
After rebooting the
system you are done.
One final note: This driver may be
ordered and installed
by anyone. It includes instructions, and does not
require dealer
intervention.
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