458 MB BIN or 399 MB ISO?

[Ken852]

I have a CD-RW here with System Rescue CD 3.7 on it.
 

TSSTcorp CDDVDW SH-224DB SB00 (SATA)
Current Profile: CD-RW

Disc Information:
Status: Complete
State of Last Session: Complete
Erasable: Yes
Sessions: 1
Sectors: 204,469
Size: 418,752,512 bytes
Time: 45:28:19 (MM:SS:FF)
MID: 97m10s00f (Ritek Co.)
Supported Read Speeds: 8x, 16x, 24x, 32x, 40x

File System Information:
Sectors: 204,471
Size: 418,756,608 bytes
Time: 45:28:21 (MM:SS:FF)

TOC Information:
Session 1... (LBA: 0 / 00:02:00)
-> Track 01  (Mode 1, LBA: 0 / 00:02:00)
-> LeadOut  (LBA: 204471 / 45:28:21)

Track Information:
Session 1...
-> Track 01 (LTSA: 0, LTS: 204469, LRA: 0)

ATIP Information:
Disc ID: 97m10s00f
Manufacturer: Ritek Co.
Start Time of LeadIn: 97m10s00f
Last Possible Start Time of LeadOut: 79m59s74f

If I make an ISO file of it, it takes up 399 MB (418,756,608 bytes). If I I make a BIN/CUE file set of it, the BIN file takes up 458 MB (480,915,792 bytes).

Why is there such a big difference in size?

At the same time, ImgBurn reports a size of 418,756,608 bytes. How do you explain this?

This CD was originally written to by using an ISO file of this software.

Should I be using ISO format when imaging software discs?

 

[Ken852]

This old version is no longer available at SourceForge:

https://sourceforge.net/projects/systemrescuecd/files/sysresccd-x86/

But it can be downloaded from the Internet Archive:

https://archive.org/details/systemrescuecd-x86-3.7.0

And as I suspected there is an ISO file and it's 399 MB in size.

 

[LIGHTNING UK!]

That disc only has a single, mode 1 track on it, so ISO would be the default extension / format.

Iso is mode 1 / ‘user data’ of a sector - 2048 bytes per sector.

Bin is for raw sectors - 2352 bytes per sector.

That’s why the bin is bigger.

[Ken852]

Raw sectors as in physical sectors on the disc? So each of these 2352 byte sectors contain a 2048 byte user data plus 304 byte control structures? This reminds me of "low level formatting" of hard drives back in the day when hard drives were about 20 GB at most.

When do I need to image to ISO and when do I need BIN/CUE or the IMG/CCD format?

I know by now that Audio CD discs should not be imaged to ISO files. But what about software discs like this one?

Are there any benefits to wasting a whopping 59 MB on a single disc like this?

[LIGHTNING UK!]

It's probably easier if you just google for the various sector formats/structures possible on a CD. There's Mode 1, Mode 2 Form 1, Mode 2 Form 2 and CD-DA.

If you look at the TOC info, you'll see if it has multiple tracks or a non Mode 1 track.

If it isn't single session/track/mode 1, use BIN.

That's what the program defaults to anyway, so just go with what it suggests.

If you want to faithfully reproduce (or emulate) the disc, you should keep its sectors in the format they're supposed to be in.