I Processing I OIL 1 If cylinder 0 is to be formatted,
read existing as Format 4 label, if present.
2 Print format message.
3 If cylinder 0 is starting cylinder,
format and write system records. I I V
FORMAT STARTED Disk
Notes
1
2 If cylinder 0 is to be formatted,
any existing as Format 4 label is
read to preserve (for IBCDASDI) the CCHH address of the next
unassigned alternate track and
also the count of the remaining
unassigned alternates. This data will be put in the new OS Format
4 label on track O. DMKFMT branches and links to the
message writing (WMSG) routine to
display
FORMAT STARTED Then It updates the I/O new PSW so
that the 10lNT routine executes when
an I/O interrupt occurs.
3 If cylinder 0 is the starting cylinder,
the FORMAT program formats
cylinder 0 by setting up the CCWs appropriate to the device type and
then branching to the STIO routine
to perform the I/O operation. Once cylinder 0 is formatted, system
records are written on it. The branch
to the CH ECKO routine is set to Nap
so that CHECKO is executed only once.
The records written on cylinder 0 are
Record Description
o Page bit map
1 IPL record
2 Checkpoint record
3 Vol1 label 4 Allocation bit map
5 Format 4 label 6 Format 5 label F3 Page size filler F4 Filler record for 2314/2319
Moduie
DMKFMT.
DMKFMT I DMKFMT
4 Format the specified cylinders.
5 If an error occurs, record it in the
cylinder bit map in Record 0 track 0 of that cylinder.
6 Print end of format message. III I II I 8 Disk (formatted) Label Ref FMT
REGFORM1 I II STORE CHECKO Notes 4
5
The appropriate device type CCWs are
set up by the Format program. Page
size records are written and verified
by the STIO routine. Control returns
to the RESUMP routine if no error
occurs. The RESUMP routine up-
dates the record numbers and the STIO routine again writes and
verifies the record. This loop con-
tinues until the last cylinder specified
is completely formatted. If an error occurs in the STIO routine, control is transferred to the 10lNT routine. The error is retried
up to 9 tImes before the message
DMKFMT736E 10 ERROR xxx CCHH R= SENSE= is displayed. The Page bit map is
updated to indicate a bad surface.
The errors that cause the Format
function to terminate are:
seek error
error in writing or reading the
home address
error writing or reading record 0 error setting file mask
error in reading count, key, data
The message
DMKFMT735E FATAL DASD I/O ERROR
is displayed and control returns to
the GETCARD routine.
6 DMKFMT displays the message
FORMAT DONE to indicate that the specified
cylinders are formatted, and then
summarizes the errors with the
message
xxx PAGE RECORDS FLAGGED
FORMAT DONE Module Label DMKFMT STORE STIO I RESUMP DMKFMT 10lNT DMKFMT CLEANUP
Ref
Diagram 3-2. The Format Function Chapter 3. The Format Service Program 67

Input o Control Cards
Notes Module 1 The messages DMKFMT
ENTER ALLOCATION DATA FOR VOLUME xxxxxx
type cyl cyl ..........
are displayed.
2 If the Allocate control statements DMKFMT
are entered via a card reader, the
switch (CDSW2) contains X'FF'. Control is transferred to the
GETCARD routine which reads the
cards. The CONSINT and VALIDATE
routines verify the control statements
and allocate processing resumes at the label REREAD. There is a branch
and link to the RMSG routine to
read from the console. The console
read is not performed in this case
because CDSW2 is X'FF'. If the allocate control statements are
entered via the console, the switch (CDSW2) contains X'OO'. The control
statements are read from the console
by branching and linking to the RMSG routine.
3 The address of the cylinder byte map DMKFMT
is loaded into register 9. The total number of cylinders specified is loaded
into register 8. The cylinder byte
map is updated for each of the
specified cylinders according to the
type indicated in the control state· Processing Output Display allocate message.
>
2 Read allocate control statements. l:JF I ENTER ALLOCATION DATA FOR VOLUME xxxxxx
3 Update Allocation Table. 4 At end of allocation, indicate the results. Table I 1111 : I AI,location I ALLOCATION RESULTS Label Ref Notes Module Label Ref ALLOCATE ment. Control Indication in
Statement Cylinder Byte Map
TEMP X'OO' PERM X'Ol' TDSK X'02' GETCARD DRCT X'04' CONSINT The map is printed after the END
statement is processed.
VALIDATE
4 The message DMKFMT FINI REREAD ALLOCATION RESULTS followed by the type corresponding
to the allocated cylinders is displayed. Finally, the message DEVICE xxx VOLUME xxXxxx ALLOCATION ENDED
REREAD
is displayed. RMSG AOKALL I INDIC Diagram 3-3. The Allocate Function
68 IBM VM/370 Service Routines Program Logic I