Chapter 1. I BCDASDI-The Virtual Disk Initialization Program
Introduction
The IBCDASDI program initializes virtual
disks. A virtualdisk- is a logical
division of a physical DASD that is used byOS and DOS for user direct access storage
space withVM/370. Por virtual disk initialization, the
following functions are performed:
1.
2.
3 ..
4.
5.
6.
Alternate tracks are assigned
those previously designated
defective.
for
as
A home address and track descriptor
record are written.IPL records are written on track 0 of
the virtual disk.
A voluae label is written on track0 of the virtual disk.
A volume table of contents(VTOC) is
constructed and written on the virtual
disk.
AnIPL program is written on track 0 of the virtual disk (if requested).
1. Surface analysis of each track is
performed (if requested.;Alternate tracks are automatically assigned, if
necessary.Por alternate track assignment, the
following functions areperformed: 1.
2.
The first available operative
alternate track is selected from those
indicated in theVTOC. The address (CCHHR) of the priaary track is written in the count field of
the selected alternate track. The
address (CCHHR) of the alternate track
is written in the count field of the
primary track.
3. TheVTOC DSCB is modified to reflect
the new status of available tracks.!£te: The IBCDASDI program does not assign
alternate tracks orperform surface
analysis for3330 or 3350 disks. INVOKING THE VIRTUAL DISK INITIILIZATICN PRCGRIM The IEC!ASDI program may be loaded as a
card deck, or as card images ontaFe. Control statements for the program can
follow the last card (or last card image)
for theprogram, or can be entered via a
separate input device.
To execute theIBCDASDI Ircgram: 1. Put a copy of the IECDISDI object deck
into your virtual card reader, or
mount and attach thetape containing
the object program.
2. Load the objectprogram from the
virtual reader on tape by issuing theCP IPt co.mand for the appropriate
virtual device address.When the
program is loaded, an ebabled wait
state is entered with the address
field of thePSi containing the
hexadecimal valueFFFP. 3. When the program is leaded and waiting
for input, signal attention from the
virtual console device. The messageDEPINE INPUT DEVICE is sent to the virtual console. Enter
the followingresFonse from the
virtual console:INPUT=type cuu type is the virtual device type of
cuu
the device containing
control statements.
device types are1402, 2400, 2501, 2520, 2540, 3420, and 3505. the Valid 1442, 3410, is the virtual device address ef
the device containing the
controlstatelents. Control statements are printed on the message output device. It the end of job,
the ENDOF JOB message is printed en the message output device and the program
enters the wait state.Chapter 1. IBCDASDI--The Virtual Disk Initializatien Program 3
Introduction
The IBCDASDI program initializes virtual
disks. A virtual
division of a physical DASD that is used by
space with
following functions are performed:
1.
2.
3 ..
4.
5.
6.
Alternate tracks are assigned
those previously designated
defective.
for
as
A home address and track descriptor
record are written.
the virtual disk.
A voluae label is written on track
A volume table of contents
constructed and written on the virtual
disk.
An
1. Surface analysis of each track is
performed (if requested.;
necessary.
following functions are
2.
The first available operative
alternate track is selected from those
indicated in the
the selected alternate track. The
address (CCHHR) of the alternate track
is written in the count field of the
primary track.
3. The
the new status of available tracks.
alternate tracks or
analysis for
card deck, or as card images on
follow the last card (or last card image)
for the
separate input device.
To execute the
into your virtual card reader, or
mount and attach the
the object program.
2. Load the object
virtual reader on tape by issuing the
virtual device address.
program is loaded, an ebabled wait
state is entered with the address
field of the
hexadecimal value
for input, signal attention from the
virtual console device. The message
the following
virtual console:
cuu
the device containing
control statements.
device types are
the device containing the
control
the END
enters the wait state.