User's Manual

XEROX LASER PRINTING SYSTEMS TAPE FORMATS MANUAL 16-1
16. 16ICL 2900 VME/B tape format
The Xerox/OSS accepts ICL 2900 tapes of variable and fixed length
blocks.
Tape formats
Each block, including label blocks but not tape marks, is preceded by
the following 6-byte preamble:
Bytes 1 through 4 Block sequence number
Bytes 5 and 6 Block length (including preamble)
Label blocks comply with ANSI label specifications beyond the 6-byte
preamble. (Refer to chapter 1 of this manual.)
Data block formats
ICL 2900 VME/B variable length data blocks include an extra 2-byte
field, in addition to the 6-byte block preamble, which contains the
offset from byte 7 to the first byte in the last or only record in the block.
The record format for a variable block tape has the following 4-byte
record preamble as shown in figure 16-1.
Bytes 1 and 2 Record length (including preamble)
Bytes 3 and 4 File management and record spanning indicators
Figure 16-1. ICL 2900 variable block data format