Good (cheap) flash memory chips?

M

Mike Matthews

Guest
I'm designing a solid state HDD* (Think USB keydrive, but IDE) and I
need to find some flash memory chips to work with. Does anyone know of
a good chip for this type of application? They will need to handle many
writes (10,000 or more), hold data with no power (or maybe with a
button cell?), and be relitively cheap on a Dollars to Gigabytes scale.
SMT DIP is best, but other packages are fine too.

Thanks,
Mike

* Yes, I know "solid state disk drive" is an oxymoron, but you get the
idea.
 
"Mike Matthews" <m1ke.m477hewz@gmail.com> wrote in message
news:1122325353.039018.30620@g49g2000cwa.googlegroups.com...
I'm designing a solid state HDD* (Think USB keydrive, but IDE) and I
need to find some flash memory chips to work with. Does anyone know of
a good chip for this type of application? They will need to handle many
writes (10,000 or more), hold data with no power (or maybe with a
button cell?), and be relitively cheap on a Dollars to Gigabytes scale.
SMT DIP is best, but other packages are fine too.

Thanks,
Mike

* Yes, I know "solid state disk drive" is an oxymoron, but you get the
idea.
Why not just use an off the shelf IDE Flash drive, or a CF card?. You will
Click to expand...
be unlikely to beat the prices you can get these for, unless you are
buying in 10000 off quantities, and most of the work has already been
done...
You make no mention of the actual capacities required from the unit. For
smaller capacities look at FRAM, but because this only comes in 'bytewide'
or serial forms, you would need to provide the IDE interface. Has probably
the best cycle life, and data retention around.

Best Wishes
 
I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives. Stacking many smaller chips will
probably be cheaper thant trying to go with a few large ones, no? I'm
hoping someone has already done a project like this and can point me to
the chip they used, as too much trial and error is budget prohibitive.

Thanks,
Mike
 
On 25 Jul 2005 14:51:04 -0700, "Mike Matthews" <m1ke.m477hewz@gmail.com> wrote:

I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives. Stacking many smaller chips will
probably be cheaper thant trying to go with a few large ones, no? I'm
hoping someone has already done a project like this and can point me to
the chip they used, as too much trial and error is budget prohibitive.

Thanks,
Mike
Click to expand...
Maybe you could hook a bunch of CF cards to a RAID controller....!
 
"Mike Matthews" <m1ke.m477hewz@gmail.com> wrote in message
news:1122325353.039018.30620@g49g2000cwa.googlegroups.com...
I'm designing a solid state HDD* (Think USB keydrive, but IDE) and I
need to find some flash memory chips to work with. Does anyone know of
a good chip for this type of application? They will need to handle
many
writes (10,000 or more), hold data with no power (or maybe with a
button cell?), and be relitively cheap on a Dollars to Gigabytes
scale.
SMT DIP is best, but other packages are fine too.

Thanks,
Mike

* Yes, I know "solid state disk drive" is an oxymoron, but you get the
idea.
Click to expand...
That's already been done. All you do is buy the adapter to fit a
Compact Flash card to an IDE cable. It's just a PC board with a socket
for the IDE cable, and a socket for the CF card. No power, no nothing,
and cheap, too, unless you buy it with the bracket to nount it in your
FDD enclosure. I think it's Addonics that makes one to fit into the
hole where your 3.5" floppy goes.

You can insert a CF card for 32MB --> 128MB --> 512MB or all the way up
to 4GB or 8GB, or else use a microdrive which is CF type 2, thicker
card. It's bootable, too. See this one:
http://www.logicsupply.com/product_info.php?products_id=380

Also you can buy an adapter to put a CF card into the PC slot in your
laptop. The adapter costs less than $15, sometimes less than $10.
Works just like another disk drive. You can also get an adapter to
connect the PCMCIA card to an IDE cable, just like above.

Wow, 2GB microdrives are under $70! They'll be coming out with a 20GB
soon. Looks like a 6GB is a couple hundred. But if you must have
flash, a 1GB is well under a hundred.
http://www.dealtime.com/xPP-Flash_Memory-sandisk_gb-2934_compactflash_ca
rd
 
"Mike Matthews" <m1ke.m477hewz@gmail.com> wrote in message
news:1122328264.484839.142790@z14g2000cwz.googlegroups.com...
I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives. Stacking many smaller chips
will
probably be cheaper thant trying to go with a few large ones, no? I'm
hoping someone has already done a project like this and can point me
to
the chip they used, as too much trial and error is budget prohibitive.

Thanks,
Mike
Click to expand...
CF cards have some intelligence in them that writes over a new spot
instead of rewriting over the same spot every time, and thus 'wearing
out' or using up the write cycles. If you can do that with just the
basic chips, then go for it. I would use the CF cards, they're so much
simpler and cheaper.
 
"Mike Harrison" <mike@whitewing.co.uk> wrote in message
news:ghvae1dod9ajll2fsgplpt4ojqku4fskpe@4ax.com...
On 25 Jul 2005 14:51:04 -0700, "Mike Matthews"
m1ke.m477hewz@gmail.com> wrote:

I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives. Stacking many smaller chips
will
probably be cheaper thant trying to go with a few large ones, no? I'm
hoping someone has already done a project like this and can point me
to
the chip they used, as too much trial and error is budget
prohibitive.

Thanks,
Mike

Maybe you could hook a bunch of CF cards to a RAID controller....!
Click to expand...
I thought mose RAIDs are SCSI. Not only that, but what will it get you?
CF cards don't 'crash' like a hard disk. Just make sure they're backed
up often.
 
On 25 Jul 2005 14:51:04 -0700 "Mike Matthews" <m1ke.m477hewz@gmail.com>
wrote in Message id:
<1122328264.484839.142790@z14g2000cwz.googlegroups.com>:

I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives.
Click to expand...
http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Products_/IDE_Products/FFD_35_IDE_Plus.htm
http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Products_/IDE_Products/FFD_25_Ultra_ATA.htm
http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Products_/SATA_Products/FFD_25_Serial_ATA.htm

Probably not cheap, though...
 
"Mike Matthews" <m1ke.m477hewz@gmail.com> wrote in message
news:1122328264.484839.142790@z14g2000cwz.googlegroups.com...
I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives. Stacking many smaller chips will
probably be cheaper thant trying to go with a few large ones, no? I'm
hoping someone has already done a project like this and can point me to
the chip they used, as too much trial and error is budget prohibitive.

Thanks,
Mike
MemTech do IDE flash drives to 13GB, and in a larger format, flash drives
Click to expand...
up to 60GB. Look at:
http://www.dpie.com/storage/at3550.html
They use capacitors, to maintain the supply long enough to guarantee a
write completes when power is removed, which allows them to use a cache
RAM, to reduce the number of memory cycles involved. In common with most
manufacturers here, they also 'walk' the sectors used, to avoid repeated
I/O on a single location, using up the memory life too quickly (they call
this 'active remap'. They also implement error recovery algorithms in the
memory.
There is a lot of work in making a drive like this. You need the IDE
interface (simple), cache controller (relatively simple), systems to
guarantee write completion (power backup), algorithms to get away from
continuously using one sector, the hardware to implement these, and then
ECC handling. You are looking at probably a years work for a couple of
people from a 'standing start', if you have not got experience in this
area...

Best Wishes
 
"JW" <none@dev.nul> wrote in message
news:ia2ce15s9c05ovmi973kpp5abuq5a2uk02@4ax.com...
On 25 Jul 2005 14:51:04 -0700 "Mike Matthews"
m1ke.m477hewz@gmail.com
wrote in Message id:
1122328264.484839.142790@z14g2000cwz.googlegroups.com>:

I'm hoping to get into the 20GB range for the drive, something not
currently offered in comercial drives.


http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Produ
Click to expand...
cts_/IDE_Products/FFD_35_IDE_Plus.htm
http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Produ
Click to expand...
cts_/IDE_Products/FFD_25_Ultra_ATA.htm
http://www.m-systems.com/site/en-US/Products/IDESCSIFFD/IDESCSIFFD/Produ
Click to expand...
cts_/SATA_Products/FFD_25_Serial_ATA.htm
That's cool, does all sorts of neat things, like it probably has a cache
of regular RAM to speed it up. If you need that. But like you say,

Probably not cheap, though...
Click to expand...
when you compare it to a 1GB compact flash card and adapter, all for
under a hundred.
 
Ah, perfect! Just what I was trying to build. Thanks a heap.

Mike


MemTech do IDE flash drives to 13GB, and in a larger format, flash drives
up to 60GB. Look at:
http://www.dpie.com/storage/at3550.html
They use capacitors, to maintain the supply long enough to guarantee a
write completes when power is removed, which allows them to use a cache
RAM, to reduce the number of memory cycles involved. In common with most
manufacturers here, they also 'walk' the sectors used, to avoid repeated
I/O on a single location, using up the memory life too quickly (they call
this 'active remap'. They also implement error recovery algorithms in the
memory.
There is a lot of work in making a drive like this. You need the IDE
interface (simple), cache controller (relatively simple), systems to
guarantee write completion (power backup), algorithms to get away from
continuously using one sector, the hardware to implement these, and then
ECC handling. You are looking at probably a years work for a couple of
people from a 'standing start', if you have not got experience in this
area...

Best Wishes
Click to expand...
 
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