And speaking of ALGOL

Nigel Williams nw at
Thu Aug 13 03:40:03 CDT 2015

> On 13 Aug 2015, at 4:41 am, Paul Koning <paulkoning at> wrote:
> I found this out when I tried to write a program that reads foreign format tapes, in particular past tape marks.  Algol can’t do that — either that, or the consultants couldn’t figure out how.

I’m assuming the sentence above is in the same era as the sentence below and with your reference to DCALGOL then you’re really referencing the Mark II.x releases of DCALGOL for the B6700 (DCALGOL was new with the B6500 family and was intended to support the Datacomm subsystem). I say Mark II since by the time of Mark III.x the stand-alone DCALGOL was merged back into the main ALGOL compiler which then supported DMALGOL for the DMS (data management support) in a single compiler. ALGOL for Mark II.x was mainly for user-space programs and lacked access to system level operations which were instead moved to ESPOL (later replaced in Mark III.x with NEWP). ESPOL could generate any operation codes through a direct pass-through so if there was a limitation dealing with tape-marks it came from the tape-drive implementation and not the programming language.

>  I started looking at other languages, but when I started asking questions about DCALGOL I got a whole lot of pushback from the system staff. They viewed questions like that with extreme suspicion.

DCALGOL allowed direct control of the communications subsystem and mistakes would potentially impact all users, so their reaction is understandable.

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