[rescue] Re: [SunRescue] OT: AS/400 stuff

James Lockwood rescue at sunhelp.org
Wed Jun 6 03:07:06 CDT 2001

On Tue, 5 Jun 2001, Ken Hansen wrote:

> It has it's own beauty - all the numbers are (in hex) F0 = "0",
> F1="1"...F9="9" - numeric fields can be packed, but I think I drank away the
> brain cells that remembered the exact scheme.

Burroughs did one better, they used 00 to represent "0", 01 for "1", and
so on.  Made dealing the BCD data a snap.  Don't remember what they called
that char set but it was a 6-bit one IIRC.

> A neat trick used back in the late 70's was to program an EEPROM with all
> the 256 addresses representing every possible EBCDIC charater, and storing
> in the address the value of the ASCII equivalent - a one-piece ASCII <->
> EBCDIC conversion...

Unfortunately now there is no true one ASCII/EBCDIC mapping table (there
are 3 in common use).  When I wrote cross-platform Unix/S370 sync software
this was a major sticking point.  We had to be extremely optimistic in
generating file/PDS element checksums because of translation variations.

Ah, IND$FILE transfers.  The semi-good old days.


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