SMF Type 21 Record
This table shows the record layout for type 21 SMF records
It's easy to report on SMF 21 data!
Spectrum SMF Writer handles the difficult SMF record parsing for you automatically. You just specify which fields you want to see.
Spectrum SMF Writer also converts the arcane date and time fields and reformats them into an attractive report.
Record length. This field and the next field (total of four bytes) form the RDW (record descriptor word). See “Standard SMF Record Header” on page 13-1 for a detailed description.
Segment descriptor (see record length field).
System indicator: Bit Meaning When Set 0-2 Reserved 3-6 Version indicators* 7 Reserved.*See “Standard SMF Record Header” on page 13-1 for a detailed description.
Record type 21 (X'15').
Time since midnight, in hundredths of a second, when the record was moved into the SMF buffer.
Date when the record was moved into the SMF buffer, in the form 0cyydddF. See “Standard SMF Record Header” on page 13-1 for a detailed description.
System identification (from the SID parameter).
Length of rest of record.
Volume serial number.
Device number or device address.
Low order byte of UCB device type. Values less than X’80’ represent reel tapes. Values of X’80’ or greater represent cartridge tapes.
Number of temporary read errors (non-buffered log).
Number of temporary write errors (non-buffered log).
Number of start sub-channel (SSCH) instructions.
Number of permanent read errors.
Number of permanent write errors.
Number of noise blocks (non-buffered log).
Number of erase gaps.
Number of cleaner actions.
Tape format — 2400 and 3400 series magnetic tape units Dens Devtype Code Hex SMF21625 SMF21F62 SMF21160 SMF21F16 SMF21800 SMF21780 SMF21556 SMF21200 6250 9-track 4 D3 3424 4 C2 1600 9-track 3 C3 3424 3 42 800 9-track 2 CB 7-track 2 83 556 7-track 1 43 200 7-track 0 03
Block size of the last data set closed on the tape if the tape was demounted during CLOSE processing, not at a different time. Some programs that use EXCP do not provide a block size. This field is valid only (but still might contain zero) when bit SMF21LB is off.
DCBOFLGS. Bit SMF21OFL SMF21OUT SMF21RDB Meaning 1... .... Output tape .1.. .... Input tape (READ BACKWARD)
Tape unit serial.
Temporary read forward errors.
Temporary read backward errors.
Temporary write errors.
Number of bytes read, in units of 4096. The length of each block is rounded up to a multiple of 4096 before being counted. This count includes volume mount and verify, in addition to task I/O. Provided only for cartridge tape devices. Maximum value is X’FFFFFF’.
Number of bytes written, in units of 4096. The length of each block is rounded up to a multiple of 4096 before being counted. Provided only for cartridge tape devices. Maximum value is X’FFFFFF’.
SMF21FL1 SMF21NCT SMF21LS SMF21LB General flag bytes. Bit Meaning 1... .... SMF21BRN and SMF21BWN at 64 and 68 contain valid values. Currently this bit is on only for 3590. .1.. .... SMF21LST has a valid value. ..1. .... SMF21LBS has a valid value. ...x xxxx Reserved.
Number of bytes read, in units of 4096. The length of each block is rounded up to a multiple of 4096 before being counted. Valid only if SMF21NCT is on. If the value is less than X’FFFFFF’, it is also in SMF21BR.
Number of bytes written, in units of 4096. The length of each block is rounded up to a multiple of 4096 before being counted. Valid only if SMF21NCT is on. If the value is less than X’FFFFFF’, it is also in SMF`21BW.
Number of I/Os initiated on current volume. Valid only if SMF21LS is on.
Block size. Valid only if SMF21LB is on.
Number of bytes read by the device, in units of 4096. Valid only if SMF21DBV is on.
Number of bytes written by the device, in units of 4096. Valid only if SMF21DBV is on.
The table above is based on the description provided by IBM in its "MVS Systems Management Facilities (SMF)" manual.