Re: LPC or PCI design?


"John Bordynuik" <news@xxxxxxxxxxxxxxxxx> wrote in message
news:zWKFh.6252$_V2.4659@xxxxxxxxxxxxxxxxxxxxx
John Bordynuik selects "Not that I have an answer for you -- my background
is PCI -- but is that 500mb a single block of data to move, or are you
trying to move that much per second ?? (i.e. are you streaming the data
and if so, what is your peak data rate ??)"

Hi John,

Some background... I have designed many data recovery systems in the past
and what I am finding is that I need a consistent high-speed interface in
a PC to transfer pre-processed data from a custom drive . I am now having
to recover 3490E tapes (36-track) and slow the drives down to get a really
good read on really bad tapes.

I am streaming data at 5MB to 20MB/sec. I would like to interface directly
to a PC and use it to capture and process the info. It would be nice to
have an interface fast enough to allow for future designs (faster
streaming).

Most P4 PCs are selling for $260-300 off lease and cost less than a DAQ
board. Cost is an issue because I usually have large numbers of tapes to
read (thousands) and need to use many drives.

John Bordynuik


USB and FireWire both meet those specifications with rates up to or above
50MB/S (480mb/s for usb 2.0, 400mb/s or 800mb/s for FireWire)

Wide-SCSI should also be able to keep up with those kinds of rates, if your
drives are SCSI interfaced, or you build a SCSI translator

Otherwise you are looking at an atmega 32 bit microcontroller with on-chip
USB to do the grunt work of talking to the drive and pumping the data
upstream

or a similar FPGA/CPLD solution if the faster atmega chips cant keep up with
the data rate from the drive (the primary difference is that the FPGA/CPLD
solution can internally use what amounts to DMA to transfer data from the
drive to memory and memroy to USB without the microcontroller portion of the
core having to handle the data on a byte by byte basis)



.

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