flat assembler
Message board for the users of flat assembler.

Index > OS Construction > Elapsed time calculator

Goto page Previous  1, 2
Author
Thread Post new topic Reply to topic
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17662
Location: In your JS exploiting you and your system
revolution
BAiC: FAMOS runs in real mode and has no protection. This means it can still access the BIOS services, and user programs can completely take over the system.
Post 22 Feb 2014, 04:26
View user's profile Send private message Visit poster's website Reply with quote
neville



Joined: 13 Jul 2008
Posts: 507
Location: New Zealand
neville
revolution wrote:
BAiC: FAMOS runs in real mode and has no protection. This means it can still access the BIOS services, and user programs can completely take over the system.
Pehaps BAiC has now taken the trouble to read this thread more carefully and might now realise how ill-informed those comments were Wink Or perhaps not Rolling Eyes

_________________
FAMOS - the first memory operating system
Post 22 Feb 2014, 10:08
View user's profile Send private message Visit poster's website Reply with quote
BAiC



Joined: 22 Mar 2011
Posts: 272
Location: California
BAiC
Quote:
FAMOS runs in real mode and has no protection. This means it can still access the BIOS services, and user programs can completely take over the system.

revolution: the fact that one program can hijack the system is not an excuse for another program to do it. especially the operating system.

Operating Systems are about ensuring the hardare runs correctly as long as possible. an OS should not be acting like a malicious virus intent on corrupting the RTC (or any other device for that matter).

neville: have you stopped to consider whether the BIOS persists the modification? if I test your crapware on my actual machine it may very well reset my RTC to some invalid time. it's not simply about applications running in parallel. REAL HARDWARE is affected when the OS fucks up.

Quote:
Pehaps BAiC has now taken the trouble to read this thread

I did read it:

Quote:
In fact, I'm thinking it might also be useful to implement it as a FAMOS service routine.

what you want to do is damage the RTC procedurally. the method of setting the clock to zero cannot be used as a service because the second use will invalidate the first.
Post 22 Feb 2014, 15:17
View user's profile Send private message Visit poster's website Reply with quote
neville



Joined: 13 Jul 2008
Posts: 507
Location: New Zealand
neville
BAiC:
I will try to alleviate your apparent misapprehensions:
INT 1A function 0B does NOT reset the system clock! If it did, I certainly wouldn't think of using it for the purpose I described, for the very reasons you have so (eloquently?) expressed!!

INT 1A function 0B (presumably) only resets an internal BIOS day counter, which should have absolutely no effect on the RTC or on any other hardware, or on FAMOS itself. But of course it would still be subject to rigorous testing if I was ever going to consider including it in a FAMOS service routine.

However I concede that if any existing or future Application depends on the BIOS INT 1A/0A day counter then it would be affected if FAMOS, or any other app, messed with it.
This of course would be mitigated by the standard programming practice of saving the day counter before resetting it, and restoring it again afterwards.
However I also concede this this does not guarantee the validity of the day counter if one or more day roll-overs occur between the saving and restoring processes.
There are ways of fixing that problem too, but the complexity starts to increase, and the elegance correspondingly diminishes! (as M$ discovered when they created their missing day(s) bug in DOS)

But at the end of the day I can't use INT 1A function 0B or 0A because they are only available in PS/2 systems so the whole idea has become academic only.

In general of course I agree with you that any possibility of a standard BIOS function being compromised is unacceptable.

I have constructed FAMOS and many applications using the highest quality code that I can produce, using robust design and programming techniques. All of my code has also been tested as rigorously as I and any other willing people can. However you are still free to dismiss it as crapware if that is your wish Sad

BTW, I'm not aware of anybody other than myself creating applications in FAMOS, but of course I must admit it is possible. There has been a version of FAMOS with an assembly language IDE available for download since 2008.

_________________
FAMOS - the first memory operating system
Post 22 Feb 2014, 23:18
View user's profile Send private message Visit poster's website Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  
Goto page Previous  1, 2

< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2020, Tomasz Grysztar. Also on GitHub, YouTube, Twitter.

Website powered by rwasa.