2 - set to read from duplicate.

Usage:

mme    gefsye
zero   0,ARGLIST
zero   30,0

Where:

ARGLIST: points to a list of arguments for this call. The format of this list is described below.

Description:

This version of MME GEFSYE sets things up so that the next read on the given file code will be from the duplicate instead of the original. If one copy is marked defective and the other is not, the defective one is considered to be the duplicate.

The argument list indicated by ARGLIST takes the form

zero    RETURN_WORD,FC
zero    2,0

where

RETURN_WORD

points to two words where MME GEFSYE can return a status. MME GEFSYE will initialize these words to zeroes. When MME GEFSYE returns, the first word will contain

Bit 0      -- 1 to indicate completion
    1-11   -- octal error code, or 0 for success
    18-35  -- pointer to additional error info
              (if any)

See "expl mme gefsye" for a list of common error codes. In addition to the common error codes, you might see

65  -- page currently busy
66  -- file not duplicated

FC

points to a word containing the file code on which the operation will be performed. Bits 0-23 of this word should be zeroes. The file code is given in bits 24-35.

Notes:

Even if a file is sequential, random access is provided to the duplicate. Thus, when reading from the duplicate, a program must calculate initial and subsequent seek addresses, rather than relying on knowing the current position in the file and using IOS-provided seek addresses for "get next" or skip forward and backward commands.

In addition, if the file is sequential, the current position in the original file is not affected by reading from the duplicate. Therefore, when you return to the original (via MME GEFSYE (30)(3)), the file will have the position that was achieved prior to the switch.

2 - set to read from duplicate.

Usage:

Where:

Description:

Notes:

See Also: