4 ms·

Isn't the .iso "format" just a byte-by-byte dump of a disc? Just like how a .img is a byte-by-byte dump of... whatever drive? What does it mean that that one of

Isn't the .iso "format" just a byte-by-byte dump of a disc? Just like how a .img is a byte-by-byte dump of... whatever drive? What does it mean that that one of these "formats" to "die"? How do you kill a "format" that's just a straight copy of something?

DeepYogurt 2y ago
Nah, there are specific formats for isos. The full spec name is ISO_9660 https://en.wikipedia.org/wiki/ISO_9660 https://en.wikipedia.org/wiki/ISO_9660 In a certain sense you're right that in practice dumping the bytes of a disc into a file is what gave people the files, but those discs did have a structure to them. I think what's being said here is that constructing an image in the iso 9660 structure is past its time
- dataflow 2y ago
  I don't think that's what they're referring to? If that's what they mean, then it's very confusing -- and makes me think if they themselves are confused. It's like saying "we should stop shipping Joliet files" or "we should stop shipping UDF files", which makes no sense. ISO 9660 is a filesystem, not a "file format". Yet they write: > EasyOS ships as a .img file, that is written to a drive. Barry stopped shipping EasyOS as an ISO file from early 2020.
  - DeepYogurt 2y ago
    It's possible I misread it, but fair point on the .img file call out. I suppose I used to refer to .iso files as a file format given that's how I used to interact with them so that terminology read as natural to me.
- deleted 2y ago
  [deleted]
jchw 2y ago
I presume they mean the standard hybrid ISO9660 LiveCD format that Linux distros tend to use. There's a lot of nuance there that I haven't touched in years but needless to say between having multiple boot paths (I think like three--El Torito, BIOS boot sector, and UEFI) and very different media (CDROMs are, well, ROMs, thumb drives are writeable) there can be some complexity if you want to handle some more sophisticated portable OS stuff than just "run the OS installer". I'm sure this is particularly important for persistence, which can sort of be done with "traditional" live media but requires some special effort.
slashdave 2y ago
The disc (as in a CD disc) has a format specification that is recognized by the boot firmware. That is what is being copied byte-by-byte, such that the USB drive appears as if it was a CD ROM.
noirscape 2y ago
Not quite; there's cases where a .iso will actually miss certain data, since they're just dumps of what the OS recognizes as data; you tend to lose some metadata in the process. It's usually irrelevant (especially for data storage disks, which are most of the medium), until it isn't and then the format stops working. A basic example tends to be CDs with copy protection; ISO can't properly handle the protection (since the format doesn't support it), whilst the .cue/.bin format is a more accurate representation of the disk. You often don't need the disk in .cue/.bin, but in some cases you do want to store the copy protection as well (for example, with PSX emulation or if you very specifically want to digitize the disk itself, rather than the data on it.)

DeepYogurt 2y ago

Nah, there are specific formats for isos. The full spec name is ISO_9660 https://en.wikipedia.org/wiki/ISO_9660 https://en.wikipedia.org/wiki/ISO_9660 In a certain sense you're right that in practice dumping the bytes of a disc into a file is what gave people the files, but those discs did have a structure to them. I think what's being said here is that constructing an image in the iso 9660 structure is past its time

dataflow 2y ago
I don't think that's what they're referring to? If that's what they mean, then it's very confusing -- and makes me think if they themselves are confused. It's like saying "we should stop shipping Joliet files" or "we should stop shipping UDF files", which makes no sense. ISO 9660 is a filesystem, not a "file format". Yet they write: > EasyOS ships as a .img file, that is written to a drive. Barry stopped shipping EasyOS as an ISO file from early 2020.
- DeepYogurt 2y ago
  It's possible I misread it, but fair point on the .img file call out. I suppose I used to refer to .iso files as a file format given that's how I used to interact with them so that terminology read as natural to me.
deleted 2y ago
[deleted]

jchw 2y ago

I presume they mean the standard hybrid ISO9660 LiveCD format that Linux distros tend to use. There's a lot of nuance there that I haven't touched in years but needless to say between having multiple boot paths (I think like three--El Torito, BIOS boot sector, and UEFI) and very different media (CDROMs are, well, ROMs, thumb drives are writeable) there can be some complexity if you want to handle some more sophisticated portable OS stuff than just "run the OS installer". I'm sure this is particularly important for persistence, which can sort of be done with "traditional" live media but requires some special effort.

slashdave 2y ago

The disc (as in a CD disc) has a format specification that is recognized by the boot firmware. That is what is being copied byte-by-byte, such that the USB drive appears as if it was a CD ROM.

noirscape 2y ago

Not quite; there's cases where a .iso will actually miss certain data, since they're just dumps of what the OS recognizes as data; you tend to lose some metadata in the process. It's usually irrelevant (especially for data storage disks, which are most of the medium), until it isn't and then the format stops working. A basic example tends to be CDs with copy protection; ISO can't properly handle the protection (since the format doesn't support it), whilst the .cue/.bin format is a more accurate representation of the disk. You often don't need the disk in .cue/.bin, but in some cases you do want to store the copy protection as well (for example, with PSX emulation or if you very specifically want to digitize the disk itself, rather than the data on it.)