RCA301 was Re: IBM 1401 was: Re: Is it possible to use the value

Robert Wagner wrote:
> "Chuck Stevens" <charles.stevens@unisys.com> wrote:
>
> 


> Let's call this hypothetical machine CADET, for Can't Add, Doesn't Even Tr
y. It
> could do arithmetic by table lookup using two indicies. The RCA 301 actual
ly
> worked that way. If someone stepped on the arithmetic table at a fixed add
ress
> in low memory, answers came out wrong until you rebooted the machine.
>
Where were the add tables?  I know that the print translate table was in
high memory (19900-63 as I recall) because we had a program space fill
the table causing the Analex (sp?) drum printer to print and blow a
fuse.  Translate instructions used tables that started at 00 locations. 

Robert Wagner wrote:

> "Clark F. Morris, Jr." <cfmtech@istar.ca> wrote:
>
> 
>
> It
> 
>
> address
> 
>
>
> I don't recall the exact address.
Incidentally, there was no way in assembler to force a 00 starting
address even though one was needed for various tables.
>
> Everything about the RCA 301 (aka ICT1500) seemed like a joke. It had a di
sk
> drive made by Wurlitzer that looked and worked like a juke box. When an IO
 error
> occurred, the machine stopped and a red light came on. The operator was ex
pected
> to fix the record in memory (how?) and continue. It had a three-speed card
> reader that required the programmer to start downshifting about a hundred 
cards
> from the end.
We were lucky because we had the IBM card reader punch attached.  The
error correction procedure for tape was to backspace 1 block and then
read it with ALarm Inhibit (ALI) on.  The operator would then scan
memory for Memory Register Parity Error and/or Data Parity Error
(MRPE/DPE) and when found, correct the byte in memory.

>
> Perhaps the biggest joke was the tape drives. They were designed with a
> hook-and-eye fastener between the removable tape and the permanent leader.
 It
> didn't work right, so operators would dismount a tape by cutting it with a
 pair
> of scissors. The first time I saw that, I couldn't believe my eyes. To mou
nt a
> tape, they'd attach it to the leader with splicing tape.
At Westinghouse Electric International, we actually used the hook and eye.

I did like the RPG they had and DYL260 seemed to be designed with the
same philosophy.