Re: [9fans] nvram

Re: [9fans] nvram

[Russ Cox]

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The nvram is necessary for the install because
I had two choices that didn't involve changing
the kernel boot process: talk (human) installers
through typing a user name and password, or
provide an nvram file so that that particular
prompt goes away.

Since the disk is also being used to do things
like save the state of a partial install, squirrel
away VGA debugging information, and keep the vgadb
somewhere that is easily editable from a non-Plan 9
operating system, the nvram being on the floppy
is but the tip of this particular iceberg.

Russ

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From: "Boyd Roberts" <boyd@planete.net>
To: <9fans@cse.psu.edu>
Subject: [9fans] nvram
Date: Thu, 7 Sep 2000 00:47:35 +0200
Message-ID: <017c01c01854$7383a260$03c684c3@psychobasketcase.org>

why is the nvram necessary for the install?  given it's
an install there is no nvram, or if there is it contains
garbage.

i think i know why.

Re: [9fans] nvram

[Boyd Roberts]

From: Russ Cox <rsc@plan9.bell-labs.com>

> The nvram is necessary for the install because
> I had two choices that didn't involve changing
> the kernel boot process

as i thought.

[9fans] nvram

[Lyndon Nerenberg]

Okay, it's authsrv(2) that describes the nvram search sequence. And for
whatever reason I had it in my head that these days it was possible to
grab the nvram across the wire, which in hindsight makes no sense
whatsoever. And now that I think about it, my last (2ed) 'diskless' CPU
server had a floppy drive in it for this very reason ...

Doncha just love PC hardware?

--lyndon

Re: [9fans] nvram

[erik quanstrom]

On Tue Jul 28 14:00:22 EDT 2009, lyndon@orthanc.ca wrote:
> Okay, it's authsrv(2) that describes the nvram search sequence. And for
> whatever reason I had it in my head that these days it was possible to
> grab the nvram across the wire, which in hindsight makes no sense
> whatsoever. And now that I think about it, my last (2ed) 'diskless' CPU
> server had a floppy drive in it for this very reason ...
>
> Doncha just love PC hardware?

ya.  we use small flash drives from memorydepot.com for this.
but if price is really the limiter, not power or anything else,
you may prefer to use a regular hard drive.  or, i think you
could use sdloop to mount a usb key on boot and put your
nvram on that.  that might be complicated due to boot ordering
problems.

i guess i need to update this man page.  i didn't recall the
search algorithm was documented.  thanks for pointing that out.

- erik

Re: [9fans] nvram

[erik quanstrom]

> i guess i need to update this man page.  i didn't recall the
> search algorithm was documented.  thanks for pointing that out.

sorry for the obtuse reference.  now that i've made it on the list,
i'll just explain myself.  i made a local change to how
nvram is found because i kept needing to update the search to
add new drives.  sata has made it more difficult to just enumerate
the possibilities.  a vanilla machine can have 2 ahci controllers
and up to 32 drives per controller.  devsd supports up to 16 drives
per controller, which covers existing hardware.  that becomes annoying
to enumerate.  my test machine has 1 ahci, 2 ide, 1 mv50xx, 2 marvell orion
and 1 loopback controller. since the current approach requires 2 entries per
drive, i changed to this algorithm:

1.  read #S/sdctl.  gather a list of device ids.  example /dev/sdC, /dev/sdE.
2.  for each device, probe drives 0-f.  example /dev/sdE[0-f].  both
a partition named "nvram" and 9fat/plan9.nvr are probed.

note:
a.  probes on other devices are unchanged.
b.  i modified sd so that each sd device produces exactly 1 line in #S/sdctl.
the parallel scsi drivers had previously been missing.

bugs:
a.  non-sd disks like usb still can't be used with this scheme.
b.  probe order depends on the order of sd devices in your kernel
config.

one could argue that you should just plug your nvram drive into a
low-numbered port, but i kept running situations where i couldn't
use the ports i wanted due to chassis constraints.  ahci also provides
a mechanism for disabling ports, so it's anyone's guess what ports
are actually available.

this change as worked well on my personal system and at coraid
for the past 6 months.  it just works.  even on hitherto unknown
controllers like the orion.

- erik

Re: [9fans] nvram

[Dan Cross]

On Tue, Jul 28, 2009 at 2:37 PM, erik quanstrom<quanstro@quanstro.net> wrote:
> this change as worked well on my personal system and at coraid
> for the past 6 months.  it just works.  even on hitherto unknown
> controllers like the orion.

Hmm.  A few years ago, I ran into a similar problem and added a
variable that could be set in plan9.ini to specify where the nvram
actually is.  It works reasonably well....

Re: [9fans] nvram

[erik quanstrom]

> Hmm.  A few years ago, I ran into a similar problem and added a
> variable that could be set in plan9.ini to specify where the nvram
> actually is.  It works reasonably well....

difficult to maintain in a pretty active environment;
one more reason for boot failure.

- erik

Re: [9fans] nvram

[sqweek]

2009/7/29 erik quanstrom <quanstro@quanstro.net>:
>> Hmm.  A few years ago, I ran into a similar problem and added a
>> variable that could be set in plan9.ini to specify where the nvram
>> actually is.  It works reasonably well....
>
> difficult to maintain in a pretty active environment;
> one more reason for boot failure.

 Speaking of, I had a disk in my server die recently, and eventually
it affected the nvram partition. So of course, when I booted up it
couldn't read it and prompted me for the auth credentials, then tried
to write back to nvram, got an i/o error and rebooted.
 The reboot could have been caused by some other problem shortly after
(the motherboard seems to have given up on me also), but it raised the
question - does an unsuccesful write to nvram halt the boot process?
-sqweek

Re: [9fans] nvram

[erik quanstrom]

>  Speaking of, I had a disk in my server die recently, and eventually
> it affected the nvram partition. So of course, when I booted up it
> couldn't read it and prompted me for the auth credentials, then tried
> to write back to nvram, got an i/o error and rebooted.
>  The reboot could have been caused by some other problem shortly after
> (the motherboard seems to have given up on me also), but it raised the
> question - does an unsuccesful write to nvram halt the boot process?

no.  it happens to me all the time.  (when there is no
place to write nvram, as when no disk is partitioned.)

- erik

Re: [9fans] nvram

[sqweek]

2009/7/31 erik quanstrom <quanstro@quanstro.net>:
>>  Speaking of, I had a disk in my server die recently, and eventually
>> it affected the nvram partition. So of course, when I booted up it
>> couldn't read it and prompted me for the auth credentials, then tried
>> to write back to nvram, got an i/o error and rebooted.
>>  The reboot could have been caused by some other problem shortly after
>> (the motherboard seems to have given up on me also), but it raised the
>> question - does an unsuccesful write to nvram halt the boot process?
>
> no.  it happens to me all the time.  (when there is no
> place to write nvram, as when no disk is partitioned.)

 OK, but you won't hit an error in that case either. I was wondering
whether the i/o problem was tripping it up.
-sqweek

Re: [9fans] nvram

[erik quanstrom]

> >
> > no.  it happens to me all the time.  (when there is no
> > place to write nvram, as when no disk is partitioned.)
>
>  OK, but you won't hit an error in that case either. I was wondering
> whether the i/o problem was tripping it up.
> -sqweek

factotum handles this case.

- erik

Re: [9fans] nvram

[Steve Simon]

no it doesn't, I had this a few days ago, moving disks about so
nvram couldn't be found. I could still boot the system but I had to enter
the nvram info from the keyboard, it did then try to write the data back
which (of course) fails - perhaps it was this write to a dead disk that
caused the boot process to die.

-Steve

Re: [9fans] nvram

[erik quanstrom]

On Thu Jul 30 14:13:18 EDT 2009, steve@quintile.net wrote:
> no it doesn't, I had this a few days ago, moving disks about so
> nvram couldn't be found. I could still boot the system but I had to enter
> the nvram info from the keyboard, it did then try to write the data back
> which (of course) fails - perhaps it was this write to a dead disk that
> caused the boot process to die.

i hate to disagree.  but i think you may have typed your
auth information incorrectly — that does cause a panic.  but not having
a plan9.nvr or nvram partition does not.  here's a demo i
just ran:

	baxley# 9fat:
	baxley# rm /n/9fat/plan9.nvr
	baxley# echo reboot>/dev/reboot
[...]
	2040M memory: 108M kernel data, 1931M user, 2556M swap
	sdE0: LBA 3,931,200 sectors
	  SATADOM H Type rs1.a000 20090504AA0000000013 [newdrive]
	readnvram: couldn't find nvram
	can't read nvram: unknown device in # filename
	authid: bootes
	authdom: plan9.quanstro.net
	secstore key:
	password:
	can't write key to nvram: unknown device in # filename
	version...time...
	nit: starting /bin/rc
	baxley#

now if i mistype my auth information, i get

	version...authpanic: boot process died: unknown
	entication failed (auth_proxy rpc write: : bad key), trying mount anyways
	boot: mount /: attach -- unknown user or failed authentication
	dumpstack

unfortunately, at this point i'm stuck in a reboot loop and
i can only disconnect the offending media.

- erik

Re: [9fans] nvram

[Adriano Verardo]

Hi, all

I boot diskless (very obsolete PC) embedding the nvram data in the kernel.
Basically I implemented a fake-nram driver and declare it in the plan9.ini
It's just a trick but works.

If such a solution could be useful for the community I would be happy
to deliver the source.

adriano

Re: [9fans] nvram

[ron minnich]

On Tue, Jul 28, 2009 at 10:58 AM, Lyndon Nerenberg<lyndon@orthanc.ca> wrote:
> Okay, it's authsrv(2) that describes the nvram search sequence. And for
> whatever reason I had it in my head that these days it was possible to grab
> the nvram across the wire, which in hindsight makes no sense whatsoever. And
> now that I think about it, my last (2ed) 'diskless' CPU server had a floppy
> drive in it for this very reason ...
>
> Doncha just love PC hardware?


years back I modified the library so that it could use the cmos nvram.
no more disk. We used this when Andrey
put plan 9 in FLASH.

It was nice to not have any spinning media for nvram.

It gets a little tricky because cmos is not sane in where you can
store bits, but it's doable.

ron

ron

Re: [9fans] nvram

[erik quanstrom]

> years back I modified the library so that it could use the cmos nvram.
> no more disk. We used this when Andrey
> put plan 9 in FLASH.
>
> It was nice to not have any spinning media for nvram.
>
> It gets a little tricky because cmos is not sane in where you can
> store bits, but it's doable.

i don't believe this is safe for an arbitrary (rtc device, bios vendor).
i may have missed something, since some of the bios in question
are obsolete.

http://bochs.sourceforge.net/techspec/CMOS-reference.txt

- erik

Re: [9fans] nvram

[ron minnich]

On Tue, Jul 28, 2009 at 12:24 PM, erik quanstrom<quanstro@coraid.com> wrote:

> i don't believe this is safe for an arbitrary (rtc device, bios vendor).
> i may have missed something, since some of the bios in question
> are obsolete.

Hard to say. newer rtc has a whopping doubled-size CMOS and the BIOS
vendors don't seem to have used it all yet.

I think it would be worth trying to use it, but, well it is a PC, hmm.

ron

[9fans] nvram

[Sergey Reva]

Hello Fans,

Just now got interesting idea! Asked google about SPD, and...

> This is the html version of the file http://www.jedec.org/download/search/4_01_02_00R9.PDF.
> G o o g l e automatically generates html versions of documents as we crawl the web.
> To link to or bookmark this page, use the following url:
> http://www.google.com/search?q=cache:CLoDZ6X6gAIJ:www.jedec.org/download/search/4_01_02_00R9.PDF+SPD+memory+map&hl=en
> ...
> 5.10 Bytes 128-255: System Integrators specific information: The system integrator may
> choose to use the SPD ROM for various items. If so, then bytes 128-255 may be used.
> ...

Does 'Plan 9' have support for SMBus?
I found piix4smbus.c but what mean piix4?

-- 
http://rs-rlab.narod.ru                          mailto:rs_rlab@mail.ru

Re: [9fans] nvram

[Ronald G. Minnich]

piix4 is an old intel southbridge. 

I don't think you want to start using bits of SPD roms for ... what were 
you going to do again?

SMBUS is a 2-wire bus that is incredibly bad. 

ron

Re: [9fans] nvram

[Skip Tavakkolian]

> SMBUS is a 2-wire bus that is incredibly bad. 

a TukTuk?

Re: [9fans] nvram

[Dan Cross]

On Thu, May 12, 2005 at 09:47:39AM -0700, Skip Tavakkolian wrote:
> > SMBUS is a 2-wire bus that is incredibly bad. 
> 
> a TukTuk?

Those have three wheels, anyway.

	- Dan C.

[9fans] nvram

[Sergey Reva]

Hello Fans

At least in this weekend I got time to finish nvram emulation for x86.
It's 32k i2c EEPROM which concected to LPT port, of course others ic's supported too.
For now it powered from pc power supply, but i believe it can work
from LPT power too... checking now...

For testing device I read plan9.ini manual and set nvr=/dev/i2c
at this moment i can't find any way to access device driver instead of write
     char nvr[]="#2";
     bind(nvr,dev,MAFTER);
to port/initcode.c
in this case I fail with
.... can't write key to nvram: i/o error...

Then I try greping sources with 'write key to nvram', and find
/sys/src/libauthsrv/readnvram.c
after I walk though it i find many interesting, like this
nvram, nvroff, nvrlen. Then I put settings to plan9.ini
       nvram=/dev/i2c
       nvroff=0        #as i understand this is offset in file? right?
       nvrlen=512
after that all work fine

but, also I try
  cat '#2!/i2c'
and it's work, but when i write this to nvram i fail with
...file does not exist '''#2!/i2c'''....

Now I ask how use this device without changing initcode.c?
-- 
http://rs-rlab.narod.ru                          mailto:rs_rlab@mail.ru

Re: [9fans] nvram

[Russ Cox]

>   cat '#2!/i2c'

the ! is unnecessary.  #2/i2c should be fine.
does echo hello world >'#2/i2c' also work?

> and it's work, but when i write this to nvram i fail with
> ...file does not exist '''#2!/i2c'''....

your settings of nvoff and nvlen seem fine.

why are there so many quotes in that message?
you only need quotes in the shell.  maybe you
left an extra set around the name in the c table?

russ

Re: [9fans] nvram

[Sergey Reva]

Hello Russ

Sunday, April 3, 2005, 4:39:39 PM, you wrote:
RC> does echo hello world >'#2/i2c' also work?
    # echo test >'#2/i2c'
    # cat '#2/i2c'
all of that work fine

RC> your settings of nvoff and nvlen seem fine.
why this not documented? or it's special for cause user to read code :)

>> and it's work, but when i write this to nvram i fail with
>> ...file does not exist '''#2!/i2c'''....
RC> why are there so many quotes in that message?
RC> you only need quotes in the shell.
RC> maybe you left an extra set around the name in the c table?
yes, this problem with quotes... now fine

Thanks Russ! Also thanks to Inferno manual!

P.S.
Through minutes, sources and schematic should be appeared in my site
Does someone need that? How about legal driver name? Patch?

P.P.S.
Also I try 256 bytes EEPROM
24c02 and 24c256 are full work
Now all powered from LPT port
-- 
http://rs-rlab.narod.ru                            mailto:rs_rlab@mail.ru

Re: [9fans] nvram

[Russ Cox]

> RC> your settings of nvoff and nvlen seem fine.
> why this not documented? or it's special for 
> cause user to read code :)

we document how to use the library functions,
not how to write them.  you have to stop somewhere.
if you're going to be editing the code anyway,
you might as well have to read and understand it first.

russ

Re: [9fans] nvram

[C H Forsyth]

>>if you're going to be editing the code anyway,
>>you might as well have to read and understand it first.

careful: that might start a dangerous trend.

Re: [9fans] nvram

[Sergey Reva]

Hello Fans

If someone need this:
There is driver:
http://rs-rlab.narod.ru/files/devi2c.c
There is schematic:
http://rs-rlab.narod.ru/scr/i2c.gif
There is some notes:
http://rs-rlab.narod.ru/9nvram.html

-- 
http://rs-rlab.narod.ru                            mailto:rs_rlab@mail.ru

[9fans] NVRAM

[Kenji Arisawa]

Hello 9fans,

My CPU server equips a HDD for only 512B NVRAM.
I feel that is silly.
How are you doing?

Kenji Arisawa

Re: [9fans] NVRAM

[zfolkerts]

Hi,
I am booting my cpu servers using a floppy formatted like the following:
term% disk/format -db /386/pbs /dev/fd0disk /386/9load plan9.ini

with a plan9.ini that looks like:
ether0=type=elnk3
nvr=fd!0!plan9.nvr
bootfile=ether0!amaranth!/386/9pccpu
bootargs=tcp

In order to recieve an IP from DHCP (assuming that is what you are doing) you will need an entry in /lib/ndb/local containing the ethernet address, an IP address, and optionally some other info about the host. An example would be:

ip=172.16.1.20 sys=node0 ether=0060971baec1
	dom=node0.yourdom.dom

You obviously have to have an ethernet card supported by 9load for this to work.  The first boot you have to enter the authentication information (host owner, authdom, etc) as usual, but after that, the machine should just come up as a cpu server with no prompts.

I am curious however, as to how you would get a plan9.ini and plan9.nvr if you booted with 9pxeload. I have 3 machines with PXE cards that boot 9pxeload, but in order to have a plan9.ini or nvram, I am currently leaving a floppy in the drive and disabling boot from floppy. This works since 9load checks the floppy for a plan9.ini first, but I would like to eliminate the floppies on these machines if possible.

Zack Folkerts

On Wed, Aug 27, 2003 at 06:17:28AM +0900, Kenji Arisawa wrote:

> Hello 9fans,
>
> My CPU server equips a HDD for only 512B NVRAM.
> I feel that is silly.
> How are you doing?
>
> Kenji Arisawa

Re: [9fans] NVRAM

[Kenji Arisawa]

Thanks Zack Folkerts,

I didn't know plan9.nvr can live in fd of CPU server.
Manual says:
 >	nvr=value
 >	This is used by a file server kernel to locate a file holding
information to configure the file system.

I have a plenty of old FDDs. I would like to remove HDD from CPU server.

Kenji Arisawa

Re: [9fans] NVRAM

[ron minnich]

On Wed, 27 Aug 2003, Kenji Arisawa wrote:

> My CPU server equips a HDD for only 512B NVRAM.
> I feel that is silly.
> How are you doing?

I use CMOS for the NVRAM, and it works quite well. No need for a disk.

ron

Re: [9fans] NVRAM

[Kenji Arisawa]

Hello,

 >I use CMOS for the NVRAM, and it works quite well. No need for a disk.

How to use?
Just copy half of /dev/sdXX/nvram to '#r/nvram' ?

Kenji Arisawa

Re: [9fans] nvram

[jmk]

	i guess i should qualify that.  the real problem is that the
	bios should present (not that i'm a pc expert) a: as a: even if
	it's connected by two tin cans and a a piece of string.

indeed, some of them do exactly that. the problem comes once you've
used that facility to load something which can't do bios calls, it can
no longer find the drive it was loaded from.

Re: [9fans] nvram

[Boyd Roberts]

From: <jmk@plan9.bell-labs.com>

> indeed, some of them do exactly that. the problem comes once you've
> used that facility to load something which can't do bios calls, it can
> no longer find the drive it was loaded from.

don't i know it, but the vaio is cool.  got a 5620 style keyboard
that i really like, except mine is azerty :-)

Re: [9fans] Re: Kernighan interview (w/ Plan 9 mention)

[forsyth]

>>I took the roadsigns about this stuff seriously. When they seemed to say

>>	"don't play here if you are thick, or lazy, or both"

>>I made a simple call, and decided I fitted both categories. While its not
>>nice to have to self-assess as 'provably unsuitable for plan9' I think I
>>made the right decision. Whats more, I believe "you" all breathed a sigh
>>of relief inside when I did.

not a bit of it.  have a go.  it's character forming.

[9fans] nvram

[Boyd Roberts]

why is the nvram necessary for the install?  given it's
an install there is no nvram, or if there is it contains
garbage.

i think i know why.

Re: [9fans] nvram

[Boyd Roberts]

From: Boyd Roberts <boyd@planete.net>
> why is the nvram necessary for the install?  given it's
> an install there is no nvram, or if there is it contains
> garbage.
> 
> i think i know why.

i guess i should qualify that.  the real problem is that the
bios should present (not that i'm a pc expert) a: as a: even if
it's connected by two tin cans and a a piece of string.