FCOPY Reference Manual (32212-90008)

Chapter 5 69
FCOPY Functions
DEBLOCK
DEBLOCK
Lets you deblock blocked records. For example, you can use DEBLOCK to make smaller
records from larger ones or to copy files from systems with records that are not aligned on
two-byte word boundaries.
Syntax
;DEBLOCK= logical-record-length
Where:
logical-record-length Is a signed integer representing the length of each logical
record in the tofile. A positive integer represents the length in two-byte
words, and a negative integer represents the length in bytes.
Operation
DEBLOCK is principally used for copying tapes from other systems to an HP 3000 system.
For more information on copying foreign tapes, refer to chapter 3.
FCOPY assumes that each group of bytes or words you specify with DEBLOCK is a record.
FCOPY copies the record to the tofile and then aligns it on word boundaries.
Be careful when specifying the
logical-record-length . If the input record length is not
a multiple of the
logical-record-length you specify, any fractional remainder of the
input record is lost. Figure 5-1 illustrates this principle.
Figure 5-1. Logical Record Length
Input record: 250 bytes
------ ------ ------ ------ ------ ------
| 45 b | 45 b | 45 b | 45 b | 45 b | 25 b |
| | | | | | |
------ ------ ------ ------ ------ ------
Logical-record-length specified as 45 bytes results in:
------ ------ ------ ------ ------ ------
| 45 b | | 45 b | | 45 b | | 45 b | | 45 b | | |
| | | | | | | | | | | |
------ ------ ------ ------ ------ ------
output output output output output lost
rec #1 rec #2 rec #3 rec #4 rec #5 25 bytes