Minimum Mac OS Version For Reading A DVD Properly?

[Paralel]

Is there a minimum version of the Mac OS that is required to read a DVD properly?

I am running 7.1.2p with all the extensions necessary for it to function as well as any installation of 7.6.1, and using 3rd party software I am able to get it to recognize the DVD drive without issue. It can read everything properly, CD, CDR, CDRW, etc... but, as soon as I try to give it a proper DVD (factory pressed to rule out mastering errors) it will only show the first 2 GB of data and that's it, despite having all the necessary extensions required for understanding the UDF format properly. I have even tested it with a DVD-R with less than 2 GB of data, and it can read the entire thing just fine. Files copied from the DVD-R to the HDD of the Mac hosting the drive are checksum perfect. As such, as far as I can tell, all the software needed to read a DVD properly is functioning without issue.

Was 2GB of data for a given volume a technical limit of the Mac OS before HFS+ was introduced?

 

[Phipli]

Is there a minimum version of the Mac OS that is required to read a DVD properly?

I am running 7.1.2p with all the extensions necessary for it to function as well as any installation of 7.6.1, and using 3rd party software I am able to get it to recognize the DVD drive without issue. It can read everything properly, CD, CDR, CDRW, etc... but, as soon as I try to give it a proper DVD (factory pressed to rule out mastering errors) it will only show the first 2 GB of data and that's it, despite having all the necessary extensions required for understanding the UDF format properly. I have even tested it with a DVD-R with less than 2 GB of data, and it can read the entire thing just fine. Files copied from the DVD-R to the HDD of the Mac hosting the drive are checksum perfect. As such, as far as I can tell, all the software needed to read a DVD properly is functioning without issue.

Was 2GB of data for a given volume a technical limit of the Mac OS before HFS+ was introduced?

It's a more complicated answer than you expect because it depends on hardware and OS, but 7.5.2 and up can deal with partitions bigger than 2GB if I remember, but truthfully, you probably want a PowerPC because I think it otherwise just moves the limit to 4GB (less than 4.3).

It's a right old mess that I don't really feel like looking up the exact specifics of.

 

[gsteemso]

There's a point at which the limit rises from 2 GiB to 4, and then another point at which it rises from 4 GiB to 2 TiB. (Internally, it's going from a signed to unsigned 32-bit byte count, then to a 32-bit count of 512-byte sectors.)

 

[Realitystorm]

7.5.2 for PowerPC 2TB support. AND any system released with 7.5.2, not sure if there are any 68k systems released with that version. https://www.savagetaylor.com/2018/01/01/mac-os-standard-format-specifications-apple-kb-article-8647/

 

[Realitystorm]

Did a quick search. Mac OS 8.1 was the first system to have official UDF support. So perhaps 68k systems capable of running 8.1 can access DVDs

 

[Phipli]

7.5.2 for PowerPC 2TB support. AND any system released with 7.5.2, not sure if there are any 68k systems released with that version. https://www.savagetaylor.com/2018/01/01/mac-os-standard-format-specifications-apple-kb-article-8647/

Yeah, 7.5.2 is specifically a PowerPC release, I think it was for the first of the PCI macs? Could be wrong.

 

[Paralel]

Interesting. Thanks for the responses. Of all the issues I ran into, I never expected to hit such an odd fundamental limit of the lower numbered System 7 OS. Guess there really is some things that can't be done below a certain minimum System.

 

[Phipli]

Interesting. Thanks for the responses. Of all the issues I ran into, I never expected to hit such an odd fundamental limit of the lower numbered System 7 OS. Guess there really is some things that can't be done below a certain minimum System.

Disks were mostly about 80MB (probably about 20 to 160MB) when System 7 came out. I always find it insane that I can use a 16GB disk in an SE as long as I split it up into 2GB chunks.

 

[adespoton]

Hmm... with the backporting of HFS+ as low as System 7.1, I wonder if we could use a similar approach to backport UDF and DVD support?

This, of course, would only work for PPC Macs, unless Mac OS 8.1 actually has full 68k support (which would be awesome if true). Has anyone looked into this option? We could probably rip out the driver and shove it into a 7.1-compatible drvr extension if the 68k code exists in 8.1. Below 7.1, we'd probably have to shoehorn it directly into the System binary.