From: brian%jaguar.cs.utah.edu@cs.utah.edu (Brian Sturgill)
Subject: Re: OS/2 vs NT features list, Revision 1.5
Date: 4 Sep 92 13:58:30 MDT
Organization: University of Utah CS Dept

In article <1992Sep04.175232.31759@ans.net> db3l@ans.net (David Bolen) writes:
>Ok - guess I'll throw a few cents in...
>
>In article <1992Sep3.234501.28636@hellgate.utah.edu> brian%jaguar.cs.utah.edu@cs.utah.edu (Brian Sturgill) writes:
>
>> Can be configured with less features to use less memory than NT.
>>	 If you add OS/2 2.0's memory requirements for the
>>	 base package + TCP/IP base + MM + LAN Server Entry you get:
>>	 6 + 1 + 1 + 3 = 11 megs.  NT currently requires 12 and is
>>	 targeted to use 8 megs.  Thus I content neither has
>>	 a real edge in memory usage when counting relevant add-ons.
>
>It seems to me that if you are going to include a point in the "OS/2 has this
>NT doesn't" section, and then basically negate it with some comments that it's

Funny, I do the equivalent down in NT section and nobody complains about
that.  NT users are more laid back maybe? :-)

>just asking to be complained about.  How about having a separate section for
>areas that are not yet clear benefits to either system, but that might or
>might not be?

This whole item is intended to answer the question that comes up frequently,
doesn't OS/2 2.0 require less memory than NT. I see no reason it should
not be where it is.  The answer is yes, but if you try to get OS/2 features
up near NT levels then no, not really.


>
>For my comments on your comments.. the point is "can be configured with less
>features", and you then compare it to NT by adding all sorts of features and
>"counting relevant add-ons".  Isn't the whole point of this item that I get to
>pick what is relevant to me?  If I don't want TCP/IP or MM or Lan Server I can
>fit into 6MB right?  Doesn't that exactly agree with the title of this item?
>
>Just wondering...
>
>>#	Generic wait on multiple events/semaphores of different types.
>>	 This feature helps prevent deadlocks.  Consider the classic
>>	 deadlock example: Two processes, P1 and P2, both want
>>	 to access tape drives A and B.  P1 locks A and waits for
>>	 B, P2 locks B and waits for A. Deadlock.
>>	 With the generic wait facility you say wake me when
>>	 I have both A and B.  This mechanism prevents many
>>	 deadlock problems.  Just to clarify, it's quite possible
>>	 to do without this facility; it just makes things
>>	 easier.
>
>Since the subject is rather "generic" :-), could you be more explicit here?
>It seems from your example that this is exactly what OS/2's MuxWait semaphores
>would be used for, as they allow you to wait for multiple resources to become
>free or multiple events to occur simultaneously...
>
>If you mean strictly at a filesystem or device level do you imply not using
>semaphores at all, but that an application somehow notifies NT first of all
>the devices it will eventually want?  Does this also work if two applications
>enter the same deadlock situation via two file locks?

I'm going to add the case of MuxWait in the explaination.

>
>> Automatic stack expansion.
>>	 OS/2 2.0 does not (in the general case) have dynamic stack
>
>I guess I agree with the topic in general (being one of those who posted about
>it, but see next paragraph), but to be a little more accurate, don't you think
>this should say something like "OS/2 2.0 does not in all cases ...".  I mean,
>actually, in the "general" case it does - it's only thread 1 that doesn't -
>every other thread does.
>
>Also - does this really belong anymore in the section of NT has OS/2 doesn't?
>OS/2 does have the feature, just not in all situations.  Perhaps it could fit
>better in the "not a clear win" section I mention above.  After all, any OS/2
>application can use stack expansion if it wants, and for example, the EMX
>stuff gives it free (well, a little wasted memory) to any application, even
>for thread 1.  So at most the advantage would be that it requires less effort
>under NT, not that it isn't available.

Thread 1 is unique -- every process must have it... this is quite
an annoying misfeature of OS/2.  NT does this right, OS/2 doesn't really...
This is what the paragraph says.  You're picking at nothing.

>
>> Global VM/File Buffer Cache.
>>	 This is a common feature in most modern operating
>>	 systems.  It apparently makes disk consistency
>>	 easier to manage.
>
>My only comment about this is that I'd be careful that by putting it in this
>section without anything in the OS/2 section, it can sound like OS/2 doesn't
>provide caching.  It may not provide exactly the same sort of caching as
>NT, so that could be a point, but I wouldn't want to imply that the caching
>itself is something OS/2 doesn't have.

Even DOS has file caching these days... I don't see that it's a feature,
it's an expected detail.  The global VM/file buffer cache is something that
still make people that do OS work impressed, apparently it leads to cleaner,
easier to maintain implementations.  I again think you are just picking at
nothing.

>
>> Dynamic loadable/unloadable file system and device drivers.
>
>Similar to my previous comment - having this here and nothing in the OS/2
>section can lead to believing OS/2 has nothing in this area.  OS/2 does have
>dynamically (at boot time) installable filesystems, so perhaps some commentary
>here could indicate that the important part of this feature is the possibility
>of unloading and reloading file system and device drivers (providing that is
>what you meant - with a command line command I can unload and reload the
>drivers).

OS/2 has neither dynamically loadable nor unloadable ones...  it has device
drivers, and they can be loaded at boot time via changes in a configuration
file... but even DOS does this (though OS/2 can have installable file
systems too).  If I were comparing it against DOS this could be considered
a feature.  However I know of no modern OS that cannot do what OS/2 does.
You're just being picky.

Hmmm... though Dynamic should be Dynamically.

>> Good _documented_ debug hooks.
>
>How is this different than the _documented_ DosDebug interface under OS/2?

Good point, it's good that not everything is you just being picky.
I'll check futher and make appropriate changes (I was unaware of DosDebug).

>
>>#	NT can generically use more than 16 megs of memory.
>>	 On ISA machines that don't support DMA above
>>	 the 16 meg line OS/2 only uses the memory above
>>	 16 megs as a form of fast swap.
>
>(This is an aside - how does NT deal with this case - disable DMA entirely,
> or just keep buffers down in low memory for the purposes of DMA?)

It does a copy to/from low memory DMA buffer.

>
>>!	Has seamless support for 16-bit Windows apps on XGA and 8514 displays.
>>	 Someone said that OS/2 2.0 has this now... but I thought
>>	 otherwise.  Does the shipping version of OS/2 2.0 come
>>	 with seamless XGA support? (I'm certain it doesn't for
>>	 the 8514.)
>
>I don't think seamless XGA/8514 is shipping yet.

Yeah, I didn't think so either, but somebody griped so I felt compelled to
make sure.

>
>>OS/2 LAN Server 2.0 Advanced Package (Not available for OS/2 2.0 yet)
>> (Includes features of Entry Package above.)
>
>Just to be clear - you can use 2.0 Lan Requester clients with an Advanced
>OS/2 Lan Server.  It's just the server that has to be on OS/2 1.3.  So
>this is usable by 2.0 users today.
>--
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> \              David Bolen             \  Internet: db3l@ans.net      /
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Brian
-- 
C. Brian Sturgill                       *** OS/2 2.0 is for YOU! ***
University of Utah                  Microsoft needs some competition, but
Center for Software Science        -I- want to be one of the many using NT.
brian@cs.utah.edu; CIS: 70363,1373           :-) :-) :-)