RECELCK RECBLOK maintains the correlation of DISD storage pages to a specific cylinder location.
Also maintained is a bit map to indicate the page slots available for data page storage.
The RDEVRECS field and the BDEVPAGE field of the RDEVELCK point to BECELCK. o
8 Hexadecimal Displacement
------------ 0 4
8 BECPNT RECCYL I R*1 I B*2 RECMAP (128 pages maximum) Field
Name Field Description, Contents, Meaning BECPNT DS 1F RECCYL DS 1B RECUSED DS 1X RECMAX DS 1X BECMAP DS 1L
Bits defined in RECMAP O-=-page-is-available R*1
1 - Page has been assigned
-------------------------------------- Pointer to next RECBLOK on cbain
Cylinder address for pages in this block Number of pages currently in use Maximum numter of pages available Page allocation bit map (128 Fages maximum) Although the size of RECMIP is fixed, the maximum number of pages
available on a cylinder is device dependent. Bits corresponding to pages not physically present on a cylinder are set to 1. RECSIZE EQU (*-BECB10Kj/8 BECELOK size in doutlewords
Section 1. CP Data Areas and Centrel Blocks 89
RECPAG RECPAG retains up to 4K bytes of error recording data for eventual placement en the specified errcr recording cylinder.
Hexadecimal 1Jisplacellent ------------ 0 4
Field Name RECCCPD DS RECNXT DS RECFLAG1 DS 1!it§ RECPAGIO EQO RECPAGFR EQO RECPAGFL EQO RECPAGER EQO RECPAGFA EQO RECFLAG2 DS 1!.!!§ RECPAGFM EQO RECPAGDN EQO RECDATA DS RECPAGSZ EQU RECDATA (4088 bytes) 4X 2X 1X in RECFLAG1 -X'80-'-- X'40' X'20' X'10' X'08' 1X in RECFLAG2 --X'80'--- X'OO' 4088C Field Description, Contents, Meaning CCPE of the record 1Jisplacement to next error record
R*1 Record usage flags Page contains valid data Page is cleared Page is full of error records
Next page is unreadakle (I/C error) Page contains page frame reccrds
R*2 Record for. at flag Set in page 1 of a recording cylinder when
the cylinder is teing formatted. This flag
bit is reset when all pages are cleared.
Cylinder formatted
Data area
(*-RECPAG) /8 Size of page in doublewords (X'512') 90 IBM VM/370 Data Areas and Control Block Logic
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