[9fans] '486 terminal freezes during boot

[9fans] '486 terminal freezes during boot

[Matthew W Senecal]

When booting the Plan 9 partition on my '486 terminal, it freezes. At
boot I see this on screen:

PBS...Plan 9 From Bell Labs
dev A0 port 1F0 config 0C5A capabilities 0101 mwdma 0101
using sdC0!9fat!Plan9.ini
found 9PCDISK. attr 0x0 start 0x4a len 1441737
.650381...<lots more .>...+489424...<lots more .>...+87400=1227205
entry: 0x80100020
cpu0:61MHz 486DX (cpuid: Ax 0x0400 Dx 0x000)
dev A0 port 1F0 config 0C5A capabilities 0101 mwdma 0101 dma 00000001
rwm16
7125 free pages
28500K bytes
134100K swap

And that's where it freezes. I've let it sit for a half hour, but still
no go. I tried re-installing Plan 9 (on this '486 that's a 2-hour
chore!), re-installing it with the network card disabled, but neither
worked. The installation disk worked flawlessly, no errors, lock-ups, or
anything.

Does anyone know what might be causing this?

---Matt

*************************************************************************
*********
   There's nothing more dangerous than a resourceful idiot. ---Dilbert
*************************************************************************
*********
Matt Senecal
Logicon-INRI Division
(619)-553-4891
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.

Re: [9fans] '486 terminal freezes during boot (FIX)

[north_]

msenecal1@juno.com (Matthew W Senecal) wrote in message news:<20011123.084311.-2827.0.msenecal1@juno.com>...
> When booting the Plan 9 partition on my '486 terminal, it freezes. At
> boot I see this on screen:
>
> PBS...Plan 9 From Bell Labs
> dev A0 port 1F0 config 0C5A capabilities 0101 mwdma 0101
> using sdC0!9fat!Plan9.ini
> found 9PCDISK. attr 0x0 start 0x4a len 1441737
> .650381...<lots more .>...+489424...<lots more .>...+87400=1227205
> entry: 0x80100020
> cpu0:61MHz 486DX (cpuid: Ax 0x0400 Dx 0x000)
> dev A0 port 1F0 config 0C5A capabilities 0101 mwdma 0101 dma 00000001
> rwm16
> 7125 free pages
> 28500K bytes
> 134100K swap
>
> And that's where it freezes. I've let it sit for a half hour, but still
> no go. I tried re-installing Plan 9 (on this '486 that's a 2-hour
> chore!), re-installing it with the network card disabled, but neither
> worked. The installation disk worked flawlessly, no errors, lock-ups, or
> anything.
>
> Does anyone know what might be causing this?

Yes, I also had this same problem yesterday so I thought I'd
take a quick poke at it tonight. The following is a HOW-TO to
fix the puppy :) BTW, if u r not like me and don't have access
to multiple plan9 boxes (me 2 weeks ago) I attached a
compiled 9pcdisk kernel that will do the work shown below.
Errr this isnt an email (can u tell ive never subscribed to a
news group before?) so I'll upload the kernel to:
http://blessedchildren.virtualave.net/plan9/9pcdisk
I don't think google will let me post a binary file :(
I'm sure this will help u but if it doesnt feel free to email
me privately and maybe we can discuss the problem more. I'd
like a nicer fix put into the current 9tree for poor hackers
like myself ;)

----- start fix how-to -----
1. find the last known action performed on screen in the kernel
        XXX free pages
        YYYK bytes
        ZZZK swap
          ^--- this is found in /sys/src/9/port/page.c in pageinit()

2. who calls pageinit? a quick scan of my notes shows main() calls pageinit

3. easy enough so far :) simply add in print calls after the last 4 functions
   called in main() (main.c) to see if it hangs during any of these functions
   (schedinit()) shouldn't return
        /sys/src/9/pc/main.c
                pageinit();
                print("XXX meep! \n");
                swapinit();
                print("XXX north_ has nice socks \n");
                userinit();
                print("XXX :) \ n");
                schedinit();
                print("XXX can i get an amen?!?! \n"); /* shouldnt get here */
        }

4. mk 'CONF=pcdisk' 9pcdisk ; w/ the new main.c

5. slap the bootdisk into the troubled 486 and boot into the install procedure

6. wait.

7. wait some more. (dont u love 486? ;))

8. while we wait take the time to throw 9pcdisk onto a web server somewhere.
   the plan9 box u made it on, a nice lil freebsd box u have handy, a palm
   pilot available someplace on your network... errrr maybe that ZoomerPDA
   u have still sitting around your lab :)

9. ok, once booted into the installation program u should still have the
   inst file on the floppy. therefore all u need to do is 'startether' and
   then open a new rc terminal.
        9a. BTW, if u used a fresh install disk just skip down to 'archconfig'
            or whatever (just enough to set up ur ethernet/ppp :))

10. in rc, hget the 9pcdisk from the web server u have it on
        hget -o 9pcdisk http://192.168.1.1:8080/p9/9pcdisk

11. bust a `9fat:`
12. copy the original kernel /n/9fat/9pcdisk to /n/9fat/9pcorig or whatever

13. install your 9pcdisk in the /n/9fat/ directory ;)

14. go back to the install window and select 'finish'

15. reboot and watch the magic

Apparently what happens is the code goes into an interrupt spin waiting for
any interrupt what-so-ever. Well, I first posed this theory to myself when
I'd hit CTRL-ALT-DEL when the kernel was supposedly hung and get a big
kernel trace dump on the screen. I noticed that once that interrupt was
emulated the kernel continued to try and run because it was waiting
specifically for an interrupt. There is no other reason for the kernel to
attempt to run a normal process during an event which is supposed to set
the system into a halted state :) it should be starting shutdown tasks. So,
by printing data to the screen we automatically create an interrupt before
going into the scheduling 'loop'. This satisfies the kernel on the 486
enough to stop waiting and continue on with normal process. I was immediately
tossed into rio :) yay! Its Saturday night, though, so I thought I'd go
out and have some fun. Can't fix the entire problem tonight, I will start
tomorrow!

Best of Luck,
        north_

http://blessedchildren.virtualave.net/northern

p.s. this takes about a total of 10 minutes
p.p.s. i need money im poor hehe

Re: [9fans] '486 terminal freezes during boot (FIX)

[Matt Senecal]

North_,

Your solution worked like a charm! I never would have thought of that in a
million years...

---Matt




----------------------------------------------------------
  There's nothing more dangerous than a resourceful idiot.
----------------------------------------------------------
Matt Senecal
Northrop Grumman Information Technology
Logicon-INRI Division

E-mail: msenecal@logicon.com
Web: http://msenecal.tripod.com/
Phone: (619)-553-4891

Re: [9fans] '486 terminal freezes during boot (FIX)

[north_]

*blush*
:)
- north_