SCHN

Type

OMEGAMON Immediate command (Authorized)

Description

Scans data-only space control blocks for a string of data and displays the location. This command is used to search chained control blocks located in a data-only space for the occurrence of a specific string of data.

aSCHNc jobname,spacename,addr,string,off1,off2,plen

a

A required action character in column 1:

-

Changes to a comment character (>) after command executes.

<

Does not change to a comment character after command executes. Use this action character to repeat the command.

c

Specifies the format of the output:

B or ␢

dump format (default)

C

character only

X

hex only

jobname

The jobname or ASID in decimal of the owner of the data-only space.

spacename

The name of the data-only space.

addr

The starting address of the scan.

You can specify, modify, or pre-define an address (addr) for commands that display or modify storage or data-only spaces. An address consists of an anchor, optional modifiers, and an optional pre-defined name.

An anchor is the base address of an address specification. It can be:

absolute

The hexadecimal address.

symbolic

Up to eight alphanumeric characters, including @, #, and $.

You can supply one or more modifiers to change the location that the anchor points to. A modifier can be:

offset

A plus sign (+) or minus sign (-), followed by a hexadecimal number.

This modifier specifies a location at a known offset (positive or negative) from the anchor address.

indirect

Use a question mark (?) as the symbol for 31-bit addressing. Use a percent sign (%) as the symbol for 24-bit addressing. Use an exclamation point (!) as the symbol for 64-bit addressing.

This modifier indicates that the location pointed to is itself an address.

string

The comparison string for the scan. Either a hexadecimal string or a character string surrounded by single quotes.

off1

The offset from the beginning of the control block to the location of the comparison string. This value may be preceded by a + or - sign.

off2

The offset from the beginning of the control block to the fullword address of the next control block. This value may be preceded with a + or - sign.

plen

The length of print display. Default is one line or 16 (X'10') bytes.

SCHN scans data-only space storage until either a match to the string is found, the chain loops, or the address of the next control block is zero. When necessary, an SRB will be scheduled into the address space of the TCB owning the data-only space to be scanned.

This example shows the SCHN display for a data space.

>SCHN MYJOB,MYSPACE,1000,’TEST’,0,30,20
+Storage at 00001100 in dataspace MYSPACE, job MYJOB ASID=12
+ 0000  E3C5E2E3 40C4C1E3 C140E2D7 C1C3C540  *TEST DATA SPACE *
+ 0010  F0F1F2F3 F4F5F6F7 F8F9C1C2 C3C4C5C6  *0123456789ABCDEF* 

Because of the potential security risk associated with using SCHN, the .DSA command exists to provide an extra level of protection.

Related Information

Other Data Space and Hiperspace Storage commands: .DSA, OSPC, SLST, SSCN, and SZAP