Owner`s manual

Page 6-5Setting up Your System
If you have three identical system drives, and each drive has 10 logical units, then you
can define each physical drive as follows:
DEVTBL DSK1-9
DEVTBL DSK10-19
DEVTBL DSK20-29
If you have identical SCSI drives divided into the same number of logical units, and they
have consecutive SCSI IDs, you can identify all of them with a single DEVTBL
statement. In this case, you could define three drives of ten logical units each with this
statement:
DEVTBL DSK1-29
There are also important restrictions on how you specify DEVTBL command lines for
devices controlled by certain disk controllers. See your
System Operator’s Guide before
adding device definitions for hard disk devices.
As the computer processes the DEVTBL command line, it builds a device table in
system memory. The file system consults this device table for device assignments.
Here are some sample device names your computer might recognize:
DSK0 Logical unit zero of the System Device.
SUB5 Logical unit #5 of a hard disk subsystem drive.
MIN0 5.25" Floppy disk drive.
FLP1 3.5" Floppy disk drive.
STR0 Streaming tape unit.
MTU0 Magnetic tape unit.
TRM The generalized terminal service driver. Allows file oriented input and
output to any terminal connected to the computer.
After the computer is fully up and running, the DEVTBL command is a user command
that tells you what devices are in the device table in system memory; it also tells you
which devices are sharable among users. See your
System Commands Reference
Manual
for information.
Remember, there must be a device driver in DSK0:[1,6] (or loaded into system or user
memory), with the same name as the device listed on the DEVTBL line, and it must
have a .DVR extension.
6.5DEFINING DISK BITMAPS (BITMAP)
To write information to a disk, the AMOS file structure needs a disk allocation map (a
bitmap). The BITMAP command sets up these maps. If the disks on your computer run
under different disk controllers, then each type of disk must have its own device name
and separate bitmap areas.
Floppy disk drives, which may use diskettes in several different formats, must have a
different device defined for each type of format, even though the drives may run under
System Operator’s Guide to the System Initialization Command File, Rev. 03