Re: Remove plip(4)?

[T <bobs%thelibertytree.org@localhost>]

On Tue, 1 Nov 2022 06:17:20 -0000 (UTC), T wrote:

> On Tue, 4 Oct 2022 03:43:07 -0000 (UTC), T wrote:
> 
>> On Mon, 3 Oct 2022 22:43:21 -0400 (EDT), Mouse wrote:
>> I found a Laplink cable at a secondhand store for next to nothing so I
>> can report back if it actually works.
> 
> Harrumph, the driver doesn't work on the machine that would most likely
> need to use it, it might be due to this:
> 
> "The FreeBSD driver includes support for some specific chip sets,
> specifi-
> cally detection of some non-standard device I/O locations on the ISA
> bus. This support was not ported over to the NetBSD version of the
> driver yet."
> 
> I'll test it out on one of the other machines to see if it works and
> perhaps run a speed test vs serial, to see if there is much of a
> difference.

So, it turns out the "LapLink" cable I acquired is actually not to spec 
and has slightly different wiring than what is considered standard. The 
cable is yellow with embossed text on both sides of the connector heads, 
specifically "Parallel" and "Carbon Copy™". From what I could find via 
web searching, this cable was originally distributed for use with 
Symantec pcAnywhere software so it may be a proprietary modification of 
the standard cable wiring to make it inoperable for use with other 
software.

https://web.archive.org/web/20221121074912/https://old.pinouts.ru/
ParallelPorts/pcanywhere_cable_pinout.shtml

2			15
3			13
4			12
5			10
6			11
10			5
11			6
12			4
13			3
15			2
1,7,8,9,14,16,17			unused
18-25			18-25		Common as one


The test setup included one Linux and one NetBSD machine. Initially, a 
successful SSH session was established, however connectivity was unable 
to be replicated on subsequent attempts, which lead to verifying the 
wiring of the cable. The cable does not have a working pin 17, which 
appears to be needed for the Linux and FreeDOS implementations of the 
"crynwr" protocol. With the use of tcpdump on both systems, ping packets 
could be seen traveling from the NetBSD system to the Linux system, but 
return packets would not display on the NetBSD system.

I will try using NetBSD on both systems and see if it works, since the 
source code comment about wiring does not mention a need for pin 17. If I 
find another LapLink cable, with a working pin 17, I'll retry testing and 
see if it works.

https://gitlab.com/FreeDOS/net/crynwr/-/blob/master/DOC/CRYNWR/PLIP.DOC
---------------FreeDOS---crynwr--------------------
This is the wiring diagram for the cable necessary to link two
machines together by their parallel ports.  This is the same wiring
diagram used by a Turbo LapLink cable, available for sale from many
PC parts outlets.

1 - 1
2 - 15
3 - 13
4 - 12
5 - 10
6 - 11
7 nc
8 nc
9 nc
10 - 5
11 - 6
12 - 4
13 - 3
14 - 14
15 - 2
16 - 16
17 - 17
18 nc
19 nc
20 nc
21 nc
22 nc
23 nc
24 nc
25 - 25 (ground)

-------------Linux--------------------------------
  The cable used is a de facto standard parallel null cable -- sold as
  a "LapLink" cable by various places.  You'll need a 12-conductor
  cable to make one yourself.  The wiring is:
    SLCTIN      17 - 17
    GROUND      25 - 25
    D0->ERROR   2 - 15          15 - 2
    D1->SLCT    3 - 13          13 - 3
    D2->PAPOUT  4 - 12          12 - 4
    D3->ACK     5 - 10          10 - 5
    D4->BUSY    6 - 11          11 - 6
  Do not connect the other pins.  They are
    D5,D6,D7 are 7,8,9
    STROBE is 1, FEED is 14, INIT is 16
    extra grounds are 18,19,20,21,22,23,24

--------------NetBSD-------------------------------
 +----------------------------------------+
 |A-name	A-End	B-End	Descr.	Port/Bit |
 +----------------------------------------+
 |DATA0		2	15	Data	0/0x01   |
 |-ERROR	15	2	   	1/0x08   |
 +----------------------------------------+
 |DATA1		3	13	Data	0/0x02	 |
 |+SLCT		13	3	   	1/0x10   |
 +----------------------------------------+
 |DATA2		4	12	Data	0/0x04   |
 |+PE		12	4	   	1/0x20   |
 +----------------------------------------+
 |DATA3		5	10	Strobe	0/0x08   |
 |-ACK		10	5	   	1/0x40   |
 +----------------------------------------+
 |DATA4		6	11	Data	0/0x10   |
 |BUSY		11	6	   	1/~0x80  |
 +----------------------------------------+
 |GND		18-25	18-25	GND	-        |
 +----------------------------------------+