[Simh] pdp11 and unix

[Wilm Boerhout]

lists at openmailbox.org schreef op 29-2-2016 om 07:21:
> On Sat, 27 Feb 2016 17:32:19 -0500
> Paul Koning <paulkoning at comcast.net> wrote:
>
>> Decimal did show up at times even into the 1960s, for example in the IBM
>> 1620.  But it never made all that much sense; converting between binary
>> and decimal is quite easy even in those very old machines.  The one
>> plausible application area is business data processing where the
>> arithmetic is trivial and most of the work is I/O or other non-arithmetic
>> operations.
> IBM S/360 (1964) and follow-ons have all had hardware support for decimal
> and COBOL and PL/I on these platforms have always had native suport for the
> data type.
>
> As you might expect decimal arithmetic is used extensively in financial
> transactions and reporting since there is no problem of conversion. Money
> can be represented exactly rather than approximately as with floating
> point. Most banks still run their financial transactions on IBM hardware
> and OS for that reason among others.
>
>
This binary/decimal discussion stirred up some memories...

By the time Donald Knuth wrote his first volumes "The Art of Computer 
Programming", (1968-1970) the binary/decimal discussion was sufficently 
alive that he designed his virtual MIX computer (presumably in the years 
before publication) explicitly as "binary/decimal agnostic". This 
allowed for implementations/simulations on both binary and decimal 
platforms.

/Wilm