Which paper tape hole is bit 1?

[Allison]

>
>Subject: Re: Which paper tape hole is bit 1?
>   From: "Barry Watzman" <Watzman at neo.rr.com>
>   Date: Sat, 19 Nov 2005 09:50:58 -0500
>     To: <cctech at classiccmp.org>
>
>I have a chart of paper tape hole patterns for all 128 characters, and it
>shows the LSB (bit zero, although the chart numbers them 1-8) as the edge
>hole on the 3-hole side, with the bits in order 0 to 7 (or 1 to 8).
>
>However, one question, this chart shows the high-order bit (parity bit)
>punched for every character, no exceptions.  Was that a standard convention
>in sending ascii files to paper tape?

There were three, even, odd and stick (usually 1 but could be 0).
TTY when used with PDP-8 was stick at 1 (hole).

PDP-8 convention was stick at 1 (hole) for ascii

PDP-8 RIM format channel 8 is not used and channel 7 signals addres
or data pair (lower six bits x4 for 12 bits address and 12bits data).
This allows the 4 six bit pairs to specify and address and data 
anywhere and non consecutively.

PDP-8 BIN format bit 7 was 2 6bit addresses to follow and then the 
rest are data (six bit pairs).  The address is an origin and the
data follows in sequential locations.

Nominal PDP-8 use was short BIN loader hand toggled in. Load bin 
tape that contains small BIN format program or loads the RIM
loader for more complex programs (basic, focal).  BASIC would
then read an ascii program tape.

Some systems the 8th hole was used for data.

PDP8 convention for hole numbering is outside 3 hole side is 1 and 
numbered through 8 across.

1 2 3 S 4 5 6 7 8


Allison