TIFF and LibTiff Mail List Archive


2002.08.20 07:31 "memory allocation", by Peter Majer
2002.08.22 17:33 "Re: OT: large memory allocation in Windows", by Peter Montgomery
2002.08.22 18:45 "Re: OT: large memory allocation in Windows", by Chris 'Xenon' Hanson

2002.08.22 18:45 "Re: OT: large memory allocation in Windows", by Chris 'Xenon' Hanson

This non-forward-thinking 2Gb limit brought to you by Microsoft and Bill "Who would ever need more than 640k?" Gates. ;)

Maybe I'm missing something, but how much memory do you see accessing in a 32 bit environment? You can only address a maximum of 4 GB with 32 bits.

About 4Gb or so would be nice.

Would Bill have been a genius if he had allowed a program to use the entire addressable space of the CPU for allocating memory by extending the maximum to 4 GB?

It would have been the smart thing to do. There's no reason the OS needs to reserve half the available address space for itself. In fact, I believe other OSes use completely different address spaces for kernel and user space, allowing them each to have 4Gb of their own.

So then when someone tries to open the 4.1 GB file, someone says that he was a dope for limiting it to 4 GB.

Nope. At that point it's purely a technical limitation. But I disapprove of excaberating inherent technical limitations with poor and wasteful design.

Look, I was no fan of the 640 K limit, but I don't really see how this 2 GB is either Bill's fault or a colossal blunder on his/Microsoft's behalf. The best you could get by increasing to the absolute maximum of 4 GB is to buy sometime before people hit that ceiling.


But I still feel it was a very poor design decision in light of past history. If your OS imposes an artificial limit beyond what the actual hardware has, it's wasteful architecture.

PS - Besides, you're limited to +-2GB when using signed 32 bit integers. How can you do relative jumps greater than 2 GB with a 32 bit signed integer?

Rarely do you need to do a relative jump anywhere near that large. That would imply code block units of ungodly size. Any jump that far away is usually performed via an absolute address loaded from a variable. Relative jumps are usually measured in K, not even megabytes, much less gigabytes.

Chris - Xenon
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