| Michael N. Moran 2005-04-26, 8:45 pm |
| Smile ^_^ wrote:
> After reading the "USB Mass Storage Class Bulk-Only Transport"
> specification, I got a concept about the transmission protocol between
> my desktop PC and some portable USB devices such as external HDD and
> external DVD-RW. Despite this, I have no idea about how my desktop can
> understand the content in the storage media of the mass storage
> device. We know the file system is different between HDD and DVD-RW.
> Moreover, the file system of a optical disc maybe one of ISO9660, UDF
> or UDF bridge...etc. I think after the USB cable is attached, the
> device firmware can tell desktop its manufactory information to let
> desktop know it is a HDD, CD-RW or DVD-RW. But, how does PC know what
> kind of file system the device has?
The USB bulk-only transport is used to carry SCSI commands
and responses. The SCSI INQUIRY command returns information
about the type of device, as well as manufacturer and product
information.
> Could anybody give me any hint or reference document?
dpANS Project T10/1236-D SCSI Primary Commands - 2
Once you crank it up, its just reading blocks
(typically 512 bytes each).
The MBR (Master Boot Record) describes the partitioning
and individual partitions contain various file-systems,
--
Michael N. Moran (h) 770 516 7918
5009 Old Field Ct. (c) 678 521 5460
Kennesaw, GA, USA 30144 http://mnmoran.org
"So often times it happens, that we live our lives in chains
and we never even know we have the key."
The Eagles, "Already Gone"
The Beatles were wrong: 1 & 1 & 1 is 1
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