Talk:Device API: Difference between revisions
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= [[User:Dustin|Dustin]]'s Notes = | = [[User:Dustin|Dustin]]'s Notes = | ||
Notes on things that confused me; results are pulled from existing device implementations, possibly with errors: | Notes on things that confused me; results are pulled from existing device implementations, possibly with errors: | ||
: The volume label is assumed to occupy file 0, or at least, the data portion of the device is assumed to start with file 1 --[[User:Dustin|Dustin]] 00:18, 17 September 2006 (PDT) | |||
:: Although the fd-device assumes that the label is at file 0, that is not an assumption of the Device API generally. File 0 is undefined as far as the public API is concerned, data files are numbered starting from 1. [[User:Ian|Ian]] 13:48, 19 September 2006 (PDT) | |||
: File headers are assumed to be a part of the file structure; data in files begins at block zero (the test script seeks there) --[[User:Dustin|Dustin]] 00:18, 17 September 2006 (PDT) | |||
:: Yes. File headers may be stored in the data stream (and extracted by the Device API), or they may be stored out-of-band. The difference depends on what makes the most sense for a device. For the S3 device, it might be best to store all the file headers in a separate metadata entirely, since amrestore might call device_seek_file() many times without calling device_seek_block() at all. [[User:Ian|Ian]] 13:48, 19 September 2006 (PDT) | |||
Latest revision as of 20:48, 19 September 2006
Dustin's Notes
Notes on things that confused me; results are pulled from existing device implementations, possibly with errors:
- The volume label is assumed to occupy file 0, or at least, the data portion of the device is assumed to start with file 1 --Dustin 00:18, 17 September 2006 (PDT)
- Although the fd-device assumes that the label is at file 0, that is not an assumption of the Device API generally. File 0 is undefined as far as the public API is concerned, data files are numbered starting from 1. Ian 13:48, 19 September 2006 (PDT)
- File headers are assumed to be a part of the file structure; data in files begins at block zero (the test script seeks there) --Dustin 00:18, 17 September 2006 (PDT)
- Yes. File headers may be stored in the data stream (and extracted by the Device API), or they may be stored out-of-band. The difference depends on what makes the most sense for a device. For the S3 device, it might be best to store all the file headers in a separate metadata entirely, since amrestore might call device_seek_file() many times without calling device_seek_block() at all. Ian 13:48, 19 September 2006 (PDT)