Technical data

System Dump Analyzer
FORMAT
FORMAT
Displays a formatted list of the contents of a block of memory.
Format
FORMAT [/qualifier] location
Parameter
location
Location of the beginning of the data block. The location can be given as any
valid SDA expression.
Qualifier
/TYPE=block-type
Forces SDA to characterize and format a data block at location as the specified
type of data structure. The /TYPE qualifier thus overrides the default behavior of
the FORMAT command in determining the type of a data block, as described in
the Description section. The block-type can be the symbolic prefix of any data
structure.
Description
The FORMAT command performs the following actions:
• Characterizes a range of locations as a system data block
• Assigns, if possible, a symbol to each item of data within the block
• Displays all the data within the block
Normally, you use the FORMAT command without the /TYPE qualifier. Used in
this manner, it examines the byte in the structure that contains the type of the
structure. In most data structures, this byte occurs at an offset of 0A
16
into the
structure. If this byte does not contain a valid block type, the FORMAT command
halts with this message:
%SDA-E-INVBLKTYP, invalid block type in specified block
However, if this byte does contain a valid block type, SDA checks the next byte
(offset 0B
16
) for a secondary block type. When SDA has determined the type of
block, it searches for the symbols that correspond to that type of block.
If SDA cannot find the symbols associated with the block type it has found (or
that you specified in the /TYPE qualifier), it issues this message:
No "block-type" symbols found to format this block
If you receive this message, you might want to read additional symbols into the
SDA symbol table and retry the FORMAT command. Most symbols that define
data structures are contained within SYS$SYSTEM:SYSDEF.STB. Thus, you
would issue the following command:
$ READ SYS$SYSTEM:SYSDEF.STB
SDA–58