"Russell, Richard" <[log in to unmask]> wrote:
> The IBM 1620, first as the mod I, later as the mod II, ca. 1959-60, used
> decimal digits, with flag bits to mark the left end of a field. Addresses
> were decimal, from 0 to 59999. Floating point was first done in software,
> with separate exponent field, although one implementation, PDQ Fortran,
> derived from Fortran with Format, used excess-50 notation, using a single
> field for the number and the left-most two digits comprising the exponent.
> PDQ was about three times faster in execution, but later addition of
> hardware floating point removed that advantage. Of course the 360 soon
> removed the 1620.
Ah yes, I forgot the 1620 (and 1710). IBM's internal code name was
CADET. There was no hardware for arithmetic -- it was done with tables
starting at location 100. We used to change the tables to do octal
arithmetic. BTW, CADET was an acronym; it didn't mean "one just starting
out." It meant Can't Add, Doesn't Even Try. The Computer History Museum
at 1401 Shoreline Blvd in Sunnyvale, CA has a working 1620. They couldn't
find a card reader/punch, so that's done with an interface to a PC.
> RAR
>
> -----Original Message-----
> From: Fortran 90 List [mailto:[log in to unmask]]On Behalf
> Of [log in to unmask]
> Sent: Wednesday, March 10, 2004 4:46 PM
> To: [log in to unmask]
> Subject: Re: Data type "UNDEFINED"
>
>
> Loren P Meissner asked:
>
> > And I think in the early days, the "word" occupied by a default integer
> > was usually the smallest addressable storage unit. (Was IBM 360 the
> > first byte-addressable machine?)
>
> If by "byte addressable" you mean "less than 16 bits" the answer is no.
> The IBM 1401 had 6-bit characters, with "word mark" bits to delineate
> fields. I have the manual for the 1401 Fortran compiler. Pre-360
> successors to the 1401 included the 1460, 1440, 1410 and 7010 (or was it
> 7070?) The 1480 was planned but then not built with that label. Somebody
> told me it became the 360/20. Honeywell had a competitor for the 1400
> series called the 200. The Univac 1005 was also a character-addressable
> machine. The NCR 315 (actually built by CDC) allowed addressing 4-bit
> BCD digits, 6-bit characters or 12-bit integers that they called "slabs".
>
> Of the machines that had good-size integers and floating-point hardware,
> it is possible the 360 was the first to include byte addressing.
>
> --
> Van Snyder | What fraction of Americans believe
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