Method,of Operation
This section describes the execution of the
disk format Frograa and shows the
processing associated with:
Figure 3-1 shows the relationship of the
diagrams. • Formatting DASD space. • Allocating DASD space. • Writing a volume label.
Diagram 3-2
The Format
Function
Iiagram 3-1 describes the major
functions of the Format/Allccate program. Diagram 3-2 describes the format
function of the Format/Allocate program. Diagram 3-3 describes the allocate
function of the Format/Allccate prcgram.
Diagram 3-1
Overview of the
Formatl Allocate Program
Diagram 3-3
The Allocate Function
Figure 3-1. Key to the For.at/Allocate program Method of Operation Diagrams Chapter 3= The Format Service Program 65

Input Processing Output o Initialize the program. 2 Issue starting message.
3 If card input, read control statements
from card reader, otherwise issue
prompting message so that operator
enters control statements on
console.
At end, exit. I EXIT 4 Request volume label. 5 If format function, format the
specified cylinders. (See Diagram
3-2 for details'! 6 If Allocate function, read and
verify the volume label, then
perform the allocation specified.
(See Diagram 3-3 for details.)
7 If label only operation, write the
new CP volume label on cylinder
o head 0 record 3. Notes Module Label Ref Notes
1 DM KFMT sets up registers 15, 11, and DMKFMT DMKFMT ENTER DEVICE ADDRESS (ccu):
12 as base registers, gets the IPL device
address from the I/O old PSW, and
stores it in IPLDEV. Next, DMKFMT
prompts the entering of the device
address. locates the console by testing 009 and 01 F. If neither of these devices is availa- ble, it enters the wait state until an If the device address entered is valid, the device type is requested.
attention interruption is received from ENTER DEVICE TYPE:
the console.
The high cylinder address, highest
2 The program title DMKFMT STMSG record, and device type are initialized
depending on the device type entered. VM/370 FORMAT/ALLOCATE PROGRAM VERSION n.n If the device address entered is not
is displayed at the console. available, the error message DMKFMT730E DEV xxx NOT 3 If the switch (CDSW2) contains I'FF', DMKFMT GETCARD OPERATIONAL the reader enters the wait state until an I/O interrupt occurs. The CONSINT CONSINT routine reads the control statements
is issued and the request for a device
is repeated.
and the VALIDATE routine checks VALIDATE
that they are valid. 4 The message
ENTER DEVICE LABEL:
The prompter messages are issued. If SELECT is displayed.
the control statements are entered
through the card reader, the prompter 5 If the function being performed by
messages include the response that was the Format/Allocate program is the already specified in cards. format operation, then, if cylinder 0 is to be formatted, DMKFMT
The message DEVICEAD branches to FMT; otherwise, it
ENTER FORMAT OR ALLOCATE: REGFORM1. prompts the operator. If the operator
correctly enters FORMAT (F) or ALLOCATE (A), one of the following 6 The volume label is read and verified
by the LBLREC CCW string, then
DMKFMT branches to the
messages ALLOCATE routine.
FORMAT FUNCTION SELECTED ALLOCATE FUNCTION SELECTED 7 The CP volume label is written by
appears on the console.
Otherwise, the prompter message is
reissued. Then, the message
the LABWRITE CCW string.
Processing continues by reading the
next control statement (see Step 3). riagram 3-1. Overview of the Format/Allocate Prograa 66 IBM VM/370 Service Routines Program Logic 8 Formatted Allocated or Labeled Disk Module Label Ref DEVICEAC DEVTYPE
DMKFMT LAB
DMKFMT LAB
DMKFMT LAB
DMKFMT LABONLY