DOS ain't dead

The BDS is a data structure in the MS-DOS v4 BIO module:

https://hg.pushbx.org/ecm/msdos4/file/abb3b0dfe997/src/INC/MSBDS.INC#l94

https://hg.pushbx.org/ecm/msdos4/file/abb3b0dfe997/src/BIOS/MSDISK.ASM

https://hg.pushbx.org/ecm/msdos4/file/abb3b0dfe997/src/BIOS/MSINIT.ASM

In the msbds.inc file there is also mention of the "BDSM" which is "BDS structure for mini disk", where mini disk means extended or logical partitions on an MBR-partitioned disk.

The same structure is called Drive Data Table in the Interrupt List and in the FreeDOS kernel. DR-DOS calls it the UDSC (Unit Descriptor), see also this thread. I call it the UPB (Unit Parameter Block).

I haven't found any reference to what BDS stands for yet. My guesses would be "Basic Disk Structure" or "BIO Disk Structure" but there is no instance of these spelled out in the source tree if that's indeed what BDS stands for.

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l

Perhaps Boot Device Selection & Boot Device Selection Minidisk ?

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http://glennmcc.org/

> Perhaps Boot Device Selection & Boot Device Selection Minidisk ?

According to the tech blog at the AMI website:

https://www.ami.com/blog/2019/03/27/acronym-soup-what-is-bds/

one possibility *is* "Boot Device Selection". In short: "a BIOS function that allows a user to select and prioritize the order in which the system should attempt to boot from different media devices".

There is a page of info.

- Doug

> > Perhaps Boot Device Selection & Boot Device Selection Minidisk ?
>
> According to the tech blog at the AMI website:
>
> https://www.ami.com/blog/2019/03/27/acronym-soup-what-is-bds/
>
> one possibility *is* "Boot Device Selection". In short: "a BIOS function
> that allows a user to select and prioritize the order in which the system
> should attempt to boot from different media devices".
>
> There is a page of info.
>
> - Doug

I don't think this is actually the same as MS-DOS's. At that stage the MSBIO enumerates all file systems to which to allow access as to-be DOS drives. One of these was used to boot the MSDOS module off, and also to read config.sys from, but other than that there is no "boot device" involved and certainly no "selection".

(I replaced MSLOAD and the DOS loader in MSBIO to use my iniload/drload/inicomp/drkernpl stages for a single-file load, but that is irrelevant here.)

---
l

> I haven't found any reference to what BDS stands for yet. My guesses would
> be "Basic Disk Structure" or "BIO Disk Structure" but there is no instance
> of these spelled out in the source tree if that's indeed what BDS stands
> for.

My best guess, based on context, is either BIOS Disk Structure or BPB Data Structure.