IBM SNA Formats Bit Ordering is Opposite of Intel Convention

This article was previously published under Q130861
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SUMMARY
In conventional Intel bit ordering, the most significant bit (MSB) isnumbered 7 and the least significant bit (LSB) is numbered 0:
MSB                         LSB 7   6   5   4   3   2   1   0				
In Systems Network Architecture (SNA), IBM defined the LSB and MSB to bethe opposite of the Intel convention. The MSB is numbered 0 and the LSB isnumbered 7:
 MSB                         LSB  0   1   2   3   4   5   6   7				
You need to consider the difference in the Intel and IBM conventions wheninterpreting SNA Server traces using the IBM SNA Formats Guide (partnumber: GA27-3136-10).
MORE INFORMATION
The following is a sample message in an SNA Server SNA Formats trace:
---------------------------------------------- 13:51:52.71                      >>SEND>> EXCHANGE IDTH: 0d0000000600---- Data ----                    Byte 10                      |                      V326605DF FFFF0000 B0041000 00000000     <2f..............>00010B40 00100900 00000007 00103700     <...@..........7.>27110C08 04F0F2F0 F0F0F00F 06D4E240     <'....020000..MS@>E2D5C140 E2C5D9E5 C5D90908 F0F0F0F0     <SNA@SERVER..0000>F0F0F013 11031000 10F0F0F0 F0F0F0F0     <000......0000000>F0F0F0F0 F0F00E0E F4C1D7D5 C5E34BC3     <000000..4APNETKC>D7D6C9D5 E3C3                           <POINTC          >				
Byte 10 (=0x10) above in binary is: 0001 0000. It is read from left toright.
prodsna HIS 2000
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Article ID: 130861 - Last Review: 02/23/2014 01:05:28 - Revision: 4.1

  • Microsoft Host Integration Server 2000 Standard Edition
  • Microsoft SNA Server 2.0
  • Microsoft SNA Server 2.1
  • Microsoft SNA Server 3.0
  • Microsoft SNA Server 3.0 Service Pack 4
  • Microsoft SNA Server 4.0
  • kbnosurvey kbarchive kbinterop kbnetwork KB130861
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