27 Jan
2020
27 Jan
'20
11:36 a.m.
On Sun, Jan 26, 2020 at 2:59 PM Mattis Lind via cctalk
<cctalk at classiccmp.org> wrote:
Hello IBM BSC Experts!
I used to be one 25 years ago, but it's been that long since I've even
set up a BSC line.
I am trying to figure out the CRC algorithm used by
IBM BSC...
From this document (
http://bitsavers.trailing-edge.com/pdf/ibm/datacomm/GA27-3004-2_General_Inf…
)
I get that the CRC calculation is reset on SOH (01h) or STX (02h) and
accumulates until and including the ETX (03h). (excluding any SYN (32h)
characters).
That's a good document.
What we used as our "gold standard" in the 80s was a "Data 100"
manual
for a 3rd party BSC workstation. The documentation went way beyond
CRC-16 and message formats. It delved deeply into the whole protocol.
I don't remember the vendor, and I know I don't have a scan of it. I
was not able to quickly find a copy online but I admit I didn't search
more than a few minutes. It would be a good resource to locate.
-ethan