3. IPL the reader.
4. If a console is not located at either
address 009 or 01F, signal attention
from the console so the Format program
can establish the address of the
console.
5.
6.
7.
The prcgram title is printed. When there are no control cards in the
reader, the program requests control
statements by sending prompting
messages to the console. When control cards are in the reader,
they are processed. The prompter
messages are displayed with the
response field updated from the
control sta tements already entered
64 IBM VM/370 Service Routines Program Logic
through the card reader. The program requests additional input, which can
be entered via the reader or console.
8. The program issues messages indicating
the start or end of an operation.
9. 10. An operation in progress aay be
canceled by signaling attention from the console. Execution resumes with
the next The Format/Allocate program cancels an
operation if a an unrecoverable DASt I/O error occurs. A message indicating the cause of the error is
displayed.

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