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Programming Interface Information:
The Monitor Records are intended Programming Interfaces that allow the customer to write programs to obtain services of z/VM. |
MRSEKSEK
PrologControl Block Contents
Cross Reference
MRSEKSEK Prolog
DSECT NAME - SEKSEK
FUNCTION - Map a Monitor record.
LOCATED By -
Through the Monitor Control Area
REFERENCED CONTROL BLOCKS -
MRRECHDR Monitor Record Header
NAME - MRSEKSEK
DESCRIPTIVE NAME - Monitor Event Record
Domain 7 - Seek Domain
Record 1 - Seek Data
DESCRIPTION - Record of access arm movement ("Seek I/O") on a DASD
device or of a set paging parameter to a cache device.
Generated each time an I/O channel program containing
seek commands(s) is executed.
This record contains seek data that may enable a
user, such as an operating system developer, to tune
DASD seek scheduling algorithms. This record is NOT
intended for DASD load balancing. However, it can be
used to tune a cached minidisk to minimize the number
of tracks that must be cached.
NOTES:
-- Because of the frequency of seek I/O operations, an extremely
large number of this record will be generated. For this
reason, seek-domain monitoring should be limited to specific
devices or a specific set of devices.
-- The order in which the records are generated may not be the
order in which the commands are executed by the device.
-- The seek may not be executed by a device when there is a
permanent device error or when branching is done in the channel
program which bypasses segments.
MRSEKSEK Control Block Contents
Offsets Dec Hex Type Len Name (Dim) Description 0 0 Structure 84 SEKSEK Start of monitor record 0 0 Character 0 SEKSEK_MRHDR Record header. See MRRECHDR for details. 0 0 Character 20 MRHDR 0 0 Unsigned 2 MRHDRLEN 2 2 Unsigned 2 MRHDRZER 4 4 Unsigned 1 MRHDRDM 5 5 Unsigned 1 * 6 6 Unsigned 2 MRHDRRC 8 8 Character 8 MRHDRTOD 16 10 Character 4 * 20 14 Character 0 MRHDR_END 20 14 Unsigned 4 SEKSEK_RDEVSID Host subchannel I.D. number defined at initialization 24 18 Unsigned 2 SEKSEK_CALCURCY Last seek cylinder for previous DASD channel program executed. RDEVCYL SEKSEK_CALCURCY is deprecated and should not be used for further development. Code should be changed to use SEKSEK_CALCURCY32 defined below. For values above 'FFFF'x then this field will contain 'FFFF'x (and will not wrap). 26 1A Unsigned 2 SEKSEK_CALSKCYL First cylinder requested in seek command(s) in this real channel program. IORCYL SEKSEK_CALSKCYL is deprecated and should not be used for further development. Code should be changed to use SEKSEK_CALSKCYL32 defined below. For values above 'FFFF'x then this field will contain 'FFFF'x (and will not wrap). 28 1C Unsigned 2 SEKSEK_CALSKHD First head number requested in seek command(s) in this real channel program. IORHEAD 30 1E Bitstring 1 SEKSEK_CALFLAGS Flag byte 1... .... SEKSEK_IORDWRIT ON=This is a WRITE channel program. OFF=This is a READ channel program. .1.. .... * ..1. .... * ...1 .... * .... 1... * .... .1.. * .... ..1. * .... ...1 * 31 1F Bitstring 1 * Reserved for IBM use 32 20 Character 8 SEKSEK_VMDUSER Userid of requestor of seek command(s) in this real channel program. If 'SYSTEM', CP is the requestor. 40 28 Unsigned 4 SEKSEK_IORPOSCT Number of DASD access arm position changes within this real channel program. 44 2C Unsigned 4 SEKSEK_IORPOSSM Amount of access arm movements (displacements). Cumulative total of absolute differences, in cylinders, between successive seek operation within this real channel program SEKSEK_IORPOSSM is deprecated and should not be used for further development. Code should be changed to use SEKSEK_IOSPOSSM64 defined below. For values above 'FFFFFFFF'x then this field will contain 'FFFFFFFF'x (and will not wrap). 48 30 Unsigned 2 SEKSEK_CALECYL Final cylinder number (position after this real channel program completes). IORECYL SEKSEK_CALECYL is deprecated and should not be used for further development. Code should be changed to use SEKSEK_CALECYL32 defined below. For values above 'FFFF'x then this field will contain 'FFFF'x (and will not wrap). 50 32 Unsigned 2 SEKSEK_VDEVDEV Virtual device number of the target device. Not applicable if CP is the requestor (i.e., SEKSEK_VMDUSER = 'SYSTEM'). 52 34 Character 8 SEKSEK_CALUSER Userid of the owner of the target device. Not applicable if CP is the requestor (i.e., SEKSEK_VMDUSER = 'SYSTEM'). 60 3C Unsigned 2 SEKSEK_RDEVDEV Device number 62 3E Unsigned 2 * Reserved for IBM use 64 40 Unsigned 4 SEKSEK_CALCURCY32 Last seek cylinder for previous DASD channel program executed. RDEVCYL 68 44 Unsigned 4 SEKSEK_CALSKCYL32 First cylinder requested in seek command(s) in this real channel program. IORCYL 72 48 Character 8 SEKSEK_IORPOSSM64 72 48 Unsigned 4 SEKSEK_IORPOSSM64_HI 76 4C Unsigned 4 SEKSEK_IORPOSSM64_LO Amount of access arm movements (displacements). Cumulative total of absolute differences, in cylinders, between successive seek operation within this real channel program. 80 50 Unsigned 4 SEKSEK_CALECYL32 Final cylinder number (position after this real channel program completes). IORECYL 84 54 Character 0 SEKSEK_END
MRSEKSEK Cross Reference
Hex Hex Name Offset Length Value MRHDR 0 20 MRHDR_END 14 0 MRHDRDM 4 1 MRHDRLEN 0 2 MRHDRRC 6 2 MRHDRTOD 8 8 MRHDRZER 2 2 SEKSEK 0 84 SEKSEK_CALCURCY 18 2 SEKSEK_CALCURCY32 40 4 SEKSEK_CALECYL 30 2 SEKSEK_CALECYL32 50 4 SEKSEK_CALFLAGS 1E 1 SEKSEK_CALSKCYL 1A 2 SEKSEK_CALSKCYL32 44 4 SEKSEK_CALSKHD 1C 2 SEKSEK_CALUSER 34 8 SEKSEK_END 54 0 SEKSEK_IORDWRIT 1E 80 SEKSEK_IORPOSCT 28 4 SEKSEK_IORPOSSM 2C 4 SEKSEK_IORPOSSM64 48 8 SEKSEK_IORPOSSM64_HI 48 4 SEKSEK_IORPOSSM64_LO 4C 4 SEKSEK_MRHDR 0 0 SEKSEK_RDEVDEV 3C 2 SEKSEK_RDEVSID 14 4 SEKSEK_VDEVDEV 32 2 SEKSEK_VMDUSER 20 8
This information is based on z/VM V7R4.0.
Last updated on 10 September 2024 at 08:44:05.
Copyright IBM Corporation, 1990, 2024
