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picus_mf
Warnings : 1
New User
Joined: 09 Jun 2006
Posts: 52
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Hello,
Can any one give explanation why extra 4 bytes for variable record length and what does '4 byte BDW/RDWs' mean? |
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enrico-sorichetti
Superior Member
Joined: 14 Mar 2007
Posts: 10873
Location: italy
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they are ...
BDW Block Descriptior Word
RDW Record Description Word
the term sounds a bit funny because only the first halford is used..
both BDW and RDW are usually referred to as having the format "LLbb"
2 bytes for the length and two blank bytes |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8697
Location: Dubuque, Iowa, USA
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BDW -- Block Descriptor Word
RDW -- Record Descriptor Word
The length of a variable length record needs to be specified somehow. On the mainframe the RDW holds the length of the variable length record in the first 2 bytes; the last 2 bytes are reserved. The BDW holds the length of the block in the first 2 bytes and again the last 2 bytes are reserved. |
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ofer71
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Joined: 27 Dec 2005
Posts: 2358
Location: Israel
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