The following table shows the valid entries for positions 28, 31, and 32 of the file-description specifications for the various file types and processing methods. The methods of disk file processing include:
*-----------------------------------------------------------------------* | Processing Methods for DISK Files | *------------*--------*--------*--------*-------*-------*---------------* | ACCESS | METHOD | OPCODE | POSI- | POSI- | POSI- | EXPLANATION | | | | | TION | TION | TION | | | | | | 28 | 31 | 32 | | *------------*--------*--------*--------*-------*-------*---------------* | Random | RRN | CHAIN | Blank | Blank | Blank | Access by | | | | | | | | physical | | | | | | | | order of | | | | | | | | records | *------------*--------*--------*--------*-------*-------*---------------* | Sequential | Key | READ | Blank | Blank | I | Access by key | | | | READE | | | | sequentially | | | | READP | | | | | | | | REDPE | | | | | | | | cycle | | | | | *------------*--------*--------*--------*-------*-------*---------------* | Sequential | Within | READ | L | A or | I | Access by key | | | Limits | READE | | P | | sequentially | | | | READP | | | | controlled by | | | | REDPE | | | | record- | | | | cycle | | | | address- | | | | | | | | limits file | *------------*--------*--------*--------*-------*-------*---------------* | Sequential | RRN | READ | Blank | Blank | T | Access | | | | READE | | | | sequentially | | | | READP | | | | restricted to | | | | REDPE | | | | RRN numbers | | | | cycle | | | | in RAF file | *------------*--------*--------*--------*-------*-------*---------------*
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