Shift Confusion

[Steve Holden]

Dennis Lee Bieber wrote:

> On Thu, 24 Feb 2005 14:22:59 -0000, "Richard Brodie" <R.Brodie at rl.ac.uk>
> declaimed the following in comp.lang.python:
> 
> 
>>"John Machin" <sjmachin at lexicon.net> wrote in message
>>news:u81r111a8v82rt2uqfqd5me0obbua40k2p at 4ax.com...
>>
>>
>>>>Essentially, it should be possible to use a 'packed string' format in
>>>>Python, where as long as the characters you're sending are in the ASCII
>>>>range 0 to 127, two will fit in a byte.
>>>
>>>It should be possible, but only in a realm where phlogiston and
>>>perpetual motion machines exist.
>>
>>alt.sys.pdp10 ?
>>
> 
> 	Closest thing I know of to what is being attempted is DEC's
> RAD-50; but that was essentially just uppercase A..Z, 0..9, and a few
> punctuation marks, and packed three of them into two bytes.
> 
Another code it used was known as SIXBIT, allowing 64 different 
characters. IIRC it could cope with letters, digits and a bunch of 
punctuation - see

   http://nemesis.lonestar.org/reference/telecom/codes/sixbit.html

The DECSystem-10 used a 3-6 bit word, so you could get six sixbit 
characters to a word. In ASCII you could only get four (or, if you threw 
the parity bit away, five) characters to a word.

While its character-handling instructions weren't, as I recall, unique 
in the industry, the DECSystem-10 remains the only hardware I ever got 
to use that had instructions to handle variable byte sizes.

regards
  Steve