Hardware RO & delays [DOC2000]

Dvir Oren dviro at lucidvon.com
Fri Jan 7 10:55:38 EST 2000

> >  1.  Is there a way to tell the flash (DoC2000) to mark a certain part
> >  of it as read only?  I know I can mount a certain partition as read
> > only, but can I protect it at a lower level?

> Not per partition, but per NFTL. Yes - if you modify nftl.c to register the 
> blockdevice as readonly, then refuse to process any writes to that device, 
> you'll be fine.

What's the difference between per partition and per NFTL?  Do you 
mean that there should be /dev/nftla1 and /dev/nftlb1, as opposed 
to /dev/nftla1 and /dev/nftla2?

Is there a way to tell the flash chip itself not to touch certain areas?

> > 2.  Does the driver block the system?  I'm experience delays in

> Yes, it does all its flash access, even waiting for erases to finish, with 
> interrupts disabled.

Do you know if this is true for M-Systems' driver as well?

Are the interrupts disabled during read operations as well?  Could it 
be that the driver disables the interrupts even if the flash is not 

How long does it take it to finish?

Dvir Oren <dvir at lucidvon.com>
Lucid VON Ltd. <http://www.lucidvon.com>
Twin Towers 2,     Suite 406,     P.O.Box 159
35 Jabotinsky street, Ramat-Gan 52511, ISRAEL
Tel:+972 3 6137214         Fax:+972 3 6137215

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