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1996-07-10
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The combination of LOADER.DAT and INSTOVL.OBJ resolves the problems
associated with running Advanced and SFT NetWare 286 v2.15 on drives with
more than 1024 cylinders. A common symptom is the message "Warning! Bad
Block Table Not Accessed." The following files are included in this
solution:
INSTOVL OBJ 158520 12-07-89 10:39a
INSTOVL TXT 1138 10-18-90 4:24p
LOADER DAT 6656 02-14-90 9:30a
LOADER TXT 1174 08-16-90 1:28p
When NetWare 286 2.15 rev C first shipped, most hard drives were designed
with fewer than 1024 cylinders. Manufacturers at that time were simply
complying with the ROM BIOS INT 13h call which allows 10 bits for cylinder
specification, hence the 1024 cylinder limitation. Some manufacturers -
supposedly designing with adapter "translation mode" in mind - began to sell
drives with more than 1024 cylinders.
PROBLEM
Novell's cold boot loader uses INT 13H to read the disk information. That
means that it can only access cylinders 0 - 1023. Therefore, when LOADER.DAT
(shipped with NetWare 286 2.15c) reads sector 14 and picks up the pointer to
the Relocation Table (located at the beginning of the HOT FIX area on the
last 2% of the disk) it truncates the most significant bit(s) greater than
10. The obvious result is that it goes to some sector other than the one
where the Relocation Table actually resides, and begins to read the table
into memory.
At this point, two things can happen: 1) It does not find a null flag
indicating the end of the table and it hangs, or 2) by some twist of fate,
it finds a null flag, where it expects one, and believes that it has
successfully loaded the Relocation Table. In this case all of the bad block
information will be erroneous. The loader will jump all over the drive
trying to load unrelated blocks as if they were parts of the operating
system. This may account for those cases where files scroll across the file
server screen during boot up.
LOADER ENHANCEMENT
Once engineering identified this cold boot loader problem, they rewrote
LOADER.DAT to recognize when the pointer information located in sector 14 was
pointing to a Relocation Table beyond 1024 cylinders. The new loader simply
acknowledges that the pointer was outside its capacity with the message
"Warning! Bad Block Table Not Accessed." Having given the warning, the
loader then proceeds to load the operating system in the event that the
NET$OS.EXE has no re-directed blocks. If the operating system loads
correctly, the presumption that it was not re-directed proves true. If the
operating system does not successfully load, then the customer can presume
that the OS was re-directed and another work-around must be employed.
NETGEN ENHANCEMENT
INSTOVL.OBJ dated 12/07/89 resolves this problem by avoiding re-direction
during the NETGEN installation. With this enhancement, the bad blocks, if
encountered, are skipped.
WHAT ABOUT THE MESSAGE?
Unless you want to boot from floppy diskette, you cannot avoid the "Warning!
Bad Block Table Not Accessed" message. Remember, it only indicates that the
pointer to the Relocation Table has a bit set greater than 10th bit.
Q. How does NETGEN INSTALL and the NetWare OS access the full capacity of
my drive if the cold boot loader can only access cylinders 0 - 1023?
A. The disk driver, which is linked with the OS, or the hard drive
controller may work in a "translation mode" to reach beyond the 1024
cylinder barrier. The cold boot loader does not have the same
intelligence as the driver or controller. Consequently, until the OS
is loaded the limitation exists.
Q. When my OS fails to load from the hard drive (in this case it has
worked in the past but now fails) what are my options?
A. 1. You can boot from floppy.
2. You can install the LOADER.DAT (6656 bytes 2/14/90). If this new
loader will not successfully boot NET$OS, boot from floppy and
rename NET$OS.EXE to some other name so that the physical disk
location is reserved. Then copy NET$OS from floppy diskette(s)
to SYS:SYSTEM. This step may copy to a location which does not
have bad blocks. This procedure can be repeated until it produces
successful results or you run out of disk space.
3. When all of the above prove unsuccessful, you will want to try the
INSTOVL.OBJ (158520 bytes 12/07/89). You will need to relink the
file server utilities with this new OBJ file and then re-install
the operating system. This should solve the problem.