LANstation Failing to Read Double Density Floppies
The new floppy disk controller on the LANstation range of products, has
a greater tolerance band than on previous controllers. This however has caused problems
when the BIOS tests the disk to check what type it is.
Whenever a disk is changed, the BIOS tries to read the floppy at a
series of different bit rates. Due to the combination of the following three factors, the
LANstation may mistake 3.5" Double Density disks for 5.25".
| a) |
IBM BIOS checking for 5.25" disks before 3.5" |
| b) |
3.5" DD floppies and 5.25" DD floppies are very close in
their bit rate characteristics |
| c) |
The increased tolerance of the floppy drive will allow the BIOS to read
the first track of a 3.5" 720K disk using the 5.25" disk characteristics. |
Once the BIOS treats the disk as a 5.25" disk, it will continue to
do so until the disk is swapped. Although the first track can be read, the difference in
characteristics will not allow further access to the floppy and even a simple directory of
the disk will fail.
If you are going to use Double Density disks in a LANstation, we would
recommend a minimum ROM BIOS of 1.2.19 standard ROMs, and 1.2.20 Novell Remote Boot ROMs. |
