[psas-software] Need some help with choosing the disk the new PowerPC FC

Josh Triplett josh.trip at verizon.net
Wed Oct 12 13:49:55 PDT 2005


Andrew Greenberg wrote:
>> 16MB is enough for a kernel image and some other miscellany, but putting
>> / on it would be a tight squeeze.
> 
> Sorry, I didn't mean to imply this. I meant that we'd have to boot from
> the on-board 16 MB flash (/boot) as you suggest... and then mount some
> other kind of flash (e.g., a PCMCIA flash drive) to get access to
> everything else.

Ah, OK; sounds like a plan.

>> BTW, are we planning on using the other PCMCIA/CardBus slot for an
>> Orinoco?  Or are we going with another option for wireless?  For that
>> matter, do CardBus Orinoco cards exist, or are all Orinoco cards old
>> 16-bit PCMCIA?
> 
> Yes, we're going to use one slot on the PC Card carrier for the Orinoco.
> The card manufacturer claims it can do any combination of 16/32 and
> 3.3/5V cards.

Ah, cool.  Who is the card manufacturer?

>> Well, I haven't found any PC-104+ adapters for DoC alone, but there are
>> several other adapter boards which also include a DoC socket...
> 
> Huh. They might work. I can't tell if the DoC uses the ISA or the PCI
> bus in these; it'll take a bit more research. And I do hate adding
> another board... but it might be better cost wise.

Certainly looks that way; for example,
<http://www.emacinc.com/sbc_pc_addons/flash_drives.htm> lists:
PER-FLS-00010 ... 256 MB DiskOnChip 2000  $133.00
PER-FLS-00012 ... 576 MB DiskOnChip 2000  $323.00
PER-FLS-00016 ...   1 GB DiskOnChip 2000  $527.00

WDL Systems <http://wdlsystems.com> has even better prices:
1M2D256 DiskOnChip  256MB  $ 99
1M2D384 DiskOnChip  384MB  $141
1M2D576 DiskOnChip  576MB  $241
1M2D768 DiskOnChip  768MB  $310
1MD1024 DiskOnChip 1024MB  $393
They also offer Extended Temperature modules for slightly (~$10-$30)
more; from the DiskOnChip site
<http://m-sys.com/site/en-US/Products/DiskOnChip/DiskOnChip/Products/Modular/DOC2000.htm>:
Commercial: 0°C to +70°C
Extended: -40°C to +85°C

That's significantly less expensive than the linear flash cards, not to
mention the much higher capacity.  OTOH, the linear flash cards are
likely to be faster.  And CompactFlash is still cheaper, if we decide to
go that route.

I don't know how to find out whether a PC/104+ board will work with just
PCI-104, though.

>> AFAICT, the Linux DoC support in the MTD layer supports two separate
>> modes with corresponding devices.  /dev/nftl{a,b,c} are normal block
>> devices using the DoC built-in wear-levelling, and you can use a normal
>> filesystem on them.  (You can also make a partition table and use
>> /dev/nftl{a,b,c}{1,2,3}.)
> 
> This makes sense.
> 
>> /dev/mtd* are character devices giving raw
>> access to the flash, which you can copy a jffs2 filesystem to; you can
>> then mount the filesystem via the corresponding /dev/mtdblock* block
>> device.  So a DiskOnChip would let us go either route.
> 
> This doesn't make as much sense, but yay, maybe we can go this route.

What part doesn't make sense?

- Josh Triplett

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