Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!gsm001!gsm
From: gsm@gsm001.uucp (Geoffrey S. Mendelson)
Newsgroups: comp.sys.mac.misc
Subject: Re: IBM been goowy for along tyme
Message-ID: <1991Feb10.023034.858@gsm001.uucp>
Date: 10 Feb 91 02:30:34 GMT
References: <1991Feb9.035631.15285@gsm001.uucp> <1991Feb9.212956.12871@ux1.cso.uiuc.edu>
Organization: Geoffrey S. Mendelson -- Software Consulting
Lines: 52

>What's the difference whether your GUI support
>library is in ROM or RAM?   

       ROMs don't change much.  Either intentionaly such as bug fixes or
unitentionaly due to wild stores. 

        A stable base to develop code on is very useful, especially on a 
machine without memory protect.  

	Lets say, for sake of argument, our GUI support routines take up 128k.
Any module that uses the GUI is by default 128k bigger.  That is 128k more 
disk to store it, 128k more ram to run it, and 128k more disk transfer time
to load it.  If you are running 4 programs under a multitasking O.S. 
such as multifinder, that 128k becomes 512k.

       Programers, being an efficency based bunch, would try to short cut, or
limit the size of the GUI.  Less size means less function.  Something gets  
lost in the process.

       The complexity of the MAC rom calls is due to the amount of function
behind them. The equivalent calls in UNIX (X-windows), ms-dos (Windows)
AMIGA (the native O.S) are just as obscure and hard to use. 


	For efficency, I would hope that the ROMS are copied into RAM on
machines with MMUs.  This is because the access time of ram is much faster
than the roms currently in use.  On the other hand using a rom chip is
much cheaper than an mmu. It's sort of a poor man's memory protect.

       When the AMIGA 1000 was released the operating system code was rushed
out the door.  Unable to produce code stable enough for ROMs,
Commodore made a section of the RAM read only.  When you
you booted the machine, you had to boot with a "KICKSTART" disk, then boot
with the operating system.  If you were one of the lucky ones who had a hard
disk, you had to boot with the "KICKSTART" disk, then you could boot from
the floppy to use the hard disk.  To add injury to insult, the "KICKSTART"
process probably added $100 to the price of the machine.


If the original MAC had this feature, GUI or not, it would have never taken 
off. The "rest of us" don't want to have to boot our computers twice.  
Also at the time of the first MAC another 64k of ram for the rom
images would have added several hundred dollars to the price.  Memory did 
not become cheap until IBM and its clones started the incessant demand for it.
Remember that Steve and Steve did not see any need for more than 128k on the
MAC.  They knew about expansion slots.  They just could not conceive that 
"the rest of us" would want them.
-- 
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