Re: Re[2]: linux boot time

Re: Re[2]: linux boot time

[David Woodhouse]

rsmith@bitworks.com said:
>  I think I posted some info about my experiences a while back.... that
> may have been on the embedded list though...

> David, how many other reports besides mine to you have of the CF's
> developing a problem?  We use both SanDisk and SST CF's in a couple of
> projects and most of our failures are during the development cycle.
> Go figure... 

There was Vipin Malik's writeup at http://www.embeddedlinuxworks.com/ but 
that doesn't seem to be there any more. He was actually doing powerfail 
testing on JFFS/JFFS2 and making me fix it when it broke, but he also did 
some on CF, and obviously could do nothing when it broke. Software is _so_ 
much nicer.

Charles Manning's rants about bog-roll technology¹ are too vehement to have 
been born from anything but personal experience as well, AFAICT :)

--
dwmw2
¹ http://mhonarc.axis.se/jffs-dev/msg01267.html

Getting big flash onto motherboards. Will CF work? what will?

[Ronald G Minnich]

What's the right way to get a reasonably-sized flash part onto a commodity
motherboards, on a cluster of size 1024 nodes.

here's my problem. I'm setting up a linuxbios-based cluster of 1024 nodes.
I need about 2 Mbytes of flash, so I can get a kernel, initrd, and myrinet
driver in there for linuxbios to load and boot.

We don't want etherboot:  tried it, don't like it, won't work on myrinet
anyway. So we need a bigger flash part than is available on any P4
motherboard.

I can't just use DoC, as we have done on some motherboards, because it
takes way more than 512 or 1024 bytes of code to turn on those intel
chipsets. Also these boards use a Firmware Hub and the signalling is a bit
different (I think) than a standard FLASH part.

I think I'm stuck leaving the 512Kbyte flash part in there. Hence I need
to get an ADDITIONAL flash part on these motherboards. I had thought to
use IDE->CF adapters and put 1024 CF cards in the cluster. Note that these
parts would be read-only: on our Alpha cluster, we last updated flash 10
months ago. Some of the comments about CF reliability are a case for
concern.

Are there other options? These are 1U or .8U spaces most likely, and so a
big PCI card is out of the question -- that's needed for Myrinet. There
are no ISA slots. There are two IDE headers, and possibly a SCSI header. A
very low profile PCI card might work. The only option I was aware of was
IDE->CF adapaters. Is there something else I should look at?

thanks

ron

Re: Getting big flash onto motherboards. Will CF work? what will?

[David Woodhouse]

rminnich@lanl.gov said:
>  Are there other options? These are 1U or .8U spaces most likely, and
> so a big PCI card is out of the question -- that's needed for Myrinet.
> There are no ISA slots. There are two IDE headers, and possibly a SCSI
> header. A very low profile PCI card might work. The only option I was
> aware of was IDE->CF adapaters. Is there something else I should look
> at?

Given that you can ensure the BIOS won't get too upset -- could you glue 
some flash chips onto a DIMM?

If they're going to be read-only, I suspect you'd get away with CF though.

--
dwmw2

Re: Getting big flash onto motherboards. Will CF work? what will?

[Ronald G Minnich]

On Fri, 17 May 2002, David Woodhouse wrote:

> Given that you can ensure the BIOS won't get too upset -- could you glue
> some flash chips onto a DIMM?

We don't want to build this. Can we buy it?

> If they're going to be read-only, I suspect you'd get away with CF though.

Good to know, thanks.

ron

Re: Getting big flash onto motherboards. Will CF work? what will?

[David Woodhouse]

rminnich@lanl.gov said:
>  We don't want to build this. Can we buy it?

Dunno; I just made it up -- is it even technically possible to put flash in 
the DIMM slots of most motherboards?

--
dwmw2

Re: Getting big flash onto motherboards. Will CF work? what will?

[Ronald G Minnich]

On Fri, 17 May 2002, David Woodhouse wrote:

> Dunno; I just made it up -- is it even technically possible to put flash in
> the DIMM slots of most motherboards?

I think on SDRAM it would be doable, but i can't see anyone putting in the
effort as you have to get all the state machines right, and then you have
to convince the BIOS you're not really there.

In an earlier life I did design 2 different NICs for DRAM slots, and it
was not hard. But that was before SDRAM and its complexities.

ron

Re: Getting big flash onto motherboards. Will CF work? what will?

[Russ Dill]

> Are there other options? These are 1U or .8U spaces most likely, and so a
> big PCI card is out of the question -- that's needed for Myrinet. There
> are no ISA slots. There are two IDE headers, and possibly a SCSI header. A
> very low profile PCI card might work. The only option I was aware of was
> IDE->CF adapaters. Is there something else I should look at?

there are DOC devices that plug into IDE

Re: Getting big flash onto motherboards. Will CF work? what will?

[john riehl]

At 10:08 AM 5/17/02 -0700, Russ Dill wrote:
>
>> Are there other options? These are 1U or .8U spaces most likely, and so a
>> big PCI card is out of the question -- that's needed for Myrinet. There
>> are no ISA slots. There are two IDE headers, and possibly a SCSI header. A
>> very low profile PCI card might work. The only option I was aware of was
>> IDE->CF adapaters. Is there something else I should look at?
>
>there are DOC devices that plug into IDE
>

These are called DiskonModule  (as opposed to diskonchip).  

They come in both 40 and 44 pin connections.  They arent very big, they
look like a terminator.  Most are flat, like a hard drive (but much shorter
& smaller), some have an L-shape.

I have seen them at a lot of trade shows (comdex, etc.).   Inside the front
cover of my copy of processor magazine, there is an ad for them from
www.pqiusa.com.

The idea is that they act like an ide hard drive.   I havent used one.  I
dont know what needs to be done, driver-wise, to actually use one.

jr
john riehl

 

Re: Getting big flash onto motherboards. Will CF work? what will?

[Mike Mattice]

At 10:08 AM 5/17/02 -0700, Russ Dill wrote:
>there are DOC devices that plug into IDE

On Fri, May 17, 2002 at 11:08:28AM -0700, john riehl wrote:
> These are called DiskonModule  (as opposed to diskonchip).  

> The idea is that they act like an ide hard drive.   I havent used one.  I
> dont know what needs to be done, driver-wise, to actually use one.

ide-hd support in the kernel is pretty much all it needs.
use lilo or grub or whatever tickles your fancy.  it just looks
like a small hard drive.

Mike

Re: Getting big flash onto motherboards. Will CF work? what will?

[Robert Kaiser]

On Fri, 17 May 2002, john riehl wrote:

> At 10:08 AM 5/17/02 -0700, Russ Dill wrote:
> >
> >> Are there other options? These are 1U or .8U spaces most likely, and so a
> >> big PCI card is out of the question -- that's needed for Myrinet. There
> >> are no ISA slots. There are two IDE headers, and possibly a SCSI header. A
> >> very low profile PCI card might work. The only option I was aware of was
> >> IDE->CF adapaters. Is there something else I should look at?
> >
> >there are DOC devices that plug into IDE
> >
> 
> These are called DiskonModule  (as opposed to diskonchip).  
> 
> They come in both 40 and 44 pin connections.  They arent very big, they
> look like a terminator.  Most are flat, like a hard drive (but much shorter
> & smaller), some have an L-shape.

So, except for the form factor, what is the difference beween these and
a CompactFlash (wrt to reliabilty on power failure, etc.) ?

Rob

----------------------------------------------------------------
Robert Kaiser                          email: rkaiser@sysgo.de
SYSGO RTS GmbH
Am Pfaffenstein 14
D-55270 Klein-Winternheim / Germany    fax:   (49) 6136 9948-10

Re: Re[2]: linux boot time

[Richard A. Smith]

On Fri, 17 May 2002 16:44:43 +0100, David Woodhouse wrote:

>There was Vipin Malik's writeup at http://www.embeddedlinuxworks.com/ but 
>that doesn't seem to be there any more. He was actually doing powerfail 
>testing on JFFS/JFFS2 and making me fix it when it broke, but he also did 
>some on CF, and obviously could do nothing when it broke. Software is _so_ 
>much nicer.

Hmmmm... Do you have an e-mail address for him? I would like to get
info on the type of CF used and the specific failure mode.   

Was he testing JFFS on a CF or just powercycleing a CF under use?


--
Richard A. Smith                         Bitworks, Inc.               
rsmith@bitworks.com               501.846.5777 x204                        
Sr. Design Engineer        http://www.bitworks.com   

Re: Getting big flash onto motherboards. Will CF work? what will?

[Richard A. Smith]

On Fri, 17 May 2002 09:57:31 -0600 (MDT), Ronald G Minnich wrote:

>Are there other options? These are 1U or .8U spaces most likely, and so a
>big PCI card is out of the question -- that's needed for Myrinet. There
>are no ISA slots. There are two IDE headers, and possibly a SCSI header. A
>very low profile PCI card might work. The only option I was aware of was
>IDE->CF adapaters. Is there something else I should look at?

The IDE->CF is probally your best option. If you can't find a small
PCI card with flash on it.
I think that in read only mode you probally won't have any issues. 
Especially since these things won't power cycle much...

However if you do have  a problem...

<Shameless Plug>
Bitworks, Inc has an IDE to CF adapter that we have used in some of
our products.  We call it the BitDrive.

We could modify this board for you so that it ran off the 12V supply
rather than the 5V and add in a 5V Linear LDO regulator with a large
cap on the 5V rail such that the CF would have lots of clean power
long after the main power died.  This should insure that the CF's
don't die due to power issues.

In qty. of 1000 I'm pretty sure we can be pretty close to the cost of
purchasing an off-the-shelf adapter.

Give me me a ring if your interested.

BTW.. We could also build you a low profile Flash memory PCI card but
I think that will be more expensive.

</Shameless Plug>
--
Richard A. Smith                         Bitworks, Inc.               
rsmith@bitworks.com               479.846.5777 x104                        
Sr. Design Engineer        http://www.bitworks.com   

Re: Getting big flash onto motherboards. Will CF work? what will?

[john riehl]

At 08:51 PM 5/17/02 +0200, Robert Kaiser wrote:
>
>>> 
>> These are called DiskonModule  (as opposed to diskonchip).  
>> 
>> They come in both 40 and 44 pin connections.  They arent very big, they
>> look like a terminator.  Most are flat, like a hard drive (but much shorter
>> & smaller), some have an L-shape.
>
>So, except for the form factor, what is the difference beween these and
>a CompactFlash (wrt to reliabilty on power failure, etc.) ?
>

I dont know.  I dont know about CF.  how does cf connect to a system?  what
happens when cf loses power?  how do you write to a cf system?  can you
boot from it?

afaik, dom keeps info despite a power loss.

I have seen non-dom flash drives, arrays of flash chips with battery
backups which mimic hard drives, similar to dom.  these flash disk arrays
require power to retain their info.  These devices are NOT small, taking up
about the same size as a 5.25 floppy drive. 

jr

Re: Getting big flash onto motherboards. Will CF work? what will?

[David Woodhouse]

Russ.Dill@asu.edu said:
>  there are DOC devices that plug into IDE

Those are DiskOnModule -- they're effectively CF too, although maybe in a
different form factor. Although M-Systems do seem to have some clue about
how to do such things so perhaps they've managed to produce a _reliable_ CF
device.

--
dwmw2

Re: Getting big flash onto motherboards. Will CF work? what will?

[Robert Kaiser]

On Fri, 17 May 2002, john riehl wrote:

> At 08:51 PM 5/17/02 +0200, Robert Kaiser wrote:
> >
> >>> 
> >> These are called DiskonModule  (as opposed to diskonchip).  
> >> 
> >> They come in both 40 and 44 pin connections.  They arent very big, they
> >> look like a terminator.  Most are flat, like a hard drive (but much shorter
> >> & smaller), some have an L-shape.
> >
> >So, except for the form factor, what is the difference beween these and
> >a CompactFlash (wrt to reliabilty on power failure, etc.) ?
> >
> 
> I dont know.  I dont know about CF.  how does cf connect to a system?

Basically, a CF uses flash as storage media but looking at it's
interface, it behaves exactly like a normal IDE disk. You can actually
buy adapters (just wiring, no logic) to connect a CF to a normal IDE
connector. So it's pretty much like a DOM.

>  what
> happens when cf loses power?

I understand that when a CF loses power while a write is in progress, it
may corrupt some blocks in such a way that they can not be recovered.

> can you boot from it?

Obviously yes, since it behaves like an IDE drive.

> 
> afaik, dom keeps info despite a power loss.

So does a CF, the problem occurrs when it loses power while a write
is in progress.

Rob

----------------------------------------------------------------
Robert Kaiser                          email: rkaiser@sysgo.de
SYSGO RTS GmbH
Am Pfaffenstein 14
D-55270 Klein-Winternheim / Germany    fax:   (49) 6136 9948-10

Re: Getting big flash onto motherboards. Will CF work? what will?

[Charles Manning]

> >So, except for the form factor, what is the difference beween these and
> >a CompactFlash (wrt to reliabilty on power failure, etc.) ?
>
> I dont know.  I dont know about CF.  how does cf connect to a system?  what
> happens when cf loses power?  how do you write to a cf system?  can you
> boot from it?
>

We've been through this a few times in this mailing list.

CF conforms to the PCMCIA ATA interface. This effectively provides an IDE 
interface over PCMCIA.

There are basically three ways to hook a CF into your system:
* Through PCMCIA.
* Directly onto the bus (kinda like PCMCIA without the hotplug).
* Directly onto an IDE bus.

The last is perhaps the simplest. You hook the CF onto the IDE bus with a 
simple cable and the system just thinks it is a hard drive. Details for this 
cable are available on the Sandisk www.

-- Charles

Re: Getting big flash onto motherboards. Will CF work? what will?

[Karl Hammar]

...
> The last is perhaps the simplest. You hook the CF onto the IDE bus with a 
> simple cable and the system just thinks it is a hard drive. Details for this 
> cable are available on the Sandisk www.
> 
> -- Charles
...

I have tried to find it at www.sandisk.com, but could not find it.
Please send me the info or give an URL.

Regards,
/Karl

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