DOS ain't dead - Disassembly of setclock.com from MS-DOS v1.25 code release

tkchia

14.04.2020, 16:55

Disassembly of setclock.com from MS-DOS v1.25 code release (Announce)

In case it is useful: I recently did a disassembly of the setclock.com program included in Microsoft's code release of MS-DOS v1.25:

https://gitlab.com/tkchia/MS-DOS-disassembly/-/blob/master/v1.25/disassembly/setclock.asm

This is apparently a TSR program which reads and sets a particular type of hardware real time clock.

Thank you!

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https://gitlab.com/tkchia · https://codeberg.org/tkchia · 😴 "MOV AX,0D500H+CMOS_REG_D+NMI"

marcov

14.04.2020, 20:54

@ tkchia

Disassembly of setclock.com from MS-DOS v1.25 code release

Post reply

> In case it is useful: I recently did a disassembly of the
> setclock.com program included in Microsoft's code release of
> MS-DOS v1.25:
>
> https://gitlab.com/tkchia/MS-DOS-disassembly/-/blob/master/v1.25/disassembly/setclock.asm
>
> This is apparently a TSR program which reads and sets a particular type of
> hardware real time clock.

Isn't this a copyright violation? does the msdos license allow reverse engineering?

ecm

Düsseldorf, Germany,
14.04.2020, 21:30

@ marcov

Disassembly of setclock.com from MS-DOS v1.25 code release

Post reply

> Isn't this a copyright violation? does the msdos license allow reverse
> engineering?

The binaries are shipped with the permissively licensed MS-DOS 1.x and 2.x releases. So they do allow modifying and distributing the binaries too.

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l

tkchia

15.04.2020, 12:30

@ ecm

Disassembly of setclock.com from MS-DOS v1.25 code release

Post reply

Hello ecm, hello marcov,

> > Isn't this a copyright violation? does the msdos license allow reverse
> > engineering?
> The binaries are shipped with the
> permissively licensed MS-DOS 1.x and 2.x releases. So they do allow modifying and
> distributing the binaries too.

Well, to reduce confusion, I guess I should add a mention in my disassembly then that the MS-DOS v1.25 code is now MIT-licensed. :-)

Thank you!

---
https://gitlab.com/tkchia · https://codeberg.org/tkchia · 😴 "MOV AX,0D500H+CMOS_REG_D+NMI"