From: Eugen Leitl (eugen@leitl.org)
Date: Mon Nov 18 2002 - 03:36:20 MST
On Sun, 17 Nov 2002, William wrote:
> The main reason that PC hardware is crash-prone is that there are
> still 2 moving parts in it: the power supply (I don't see this
> changing anytime soon) and - the storage supply aka the hard disk
> drive (HDD). There is a trend toward solid state storage (SSS) that
Nonsense. You're confusing hardware defects with software defects. Power
supply and CPU fans are a major source of dead hardware, followed by hard
drive failures, and sometimes even solid state device failure (which are
rare, but will likely to increase as power density continues to increase
and structures to shrink).
> will use a variation of Electronically Erasable Programmable Read Only
> Memory (EEPROM) aka Flash memory as is common on Palm, Pocket PC and
> Zarius hand helds.
You can buy purely solid state PCs today. The OpenBrick device I mentioned
was one. They will still crash, if you run Windows on them.
> The main reason that older OSes have been crash-prone is that to
> increase the number of programs that they can run simultaneously aka
> multitasking they used shared system files e.g. DLLs and that if 2
> running applications requested the same one DLL there would be a
> "deadly embrace" and the system would be "busy". The famous 'Blue
Um deadlocks and race conditions are terribly rare in decent OSses. I
thought I mentioned uptime of years, which is typically interrupted by
hardware issues, not OS crash.
You're blowing heavy smoke here.
> Screen of Death" is the result. To give each application its own
> personal copy of the entire OS so that this cannot occur, means
> requiring a great deal of memory. Memory, until recent years, has
> been tremendously expensive thus this "protected mode" in which each
> app gets its own OS copy was only implemented for mission critical
> business machines e.g. UNIX, NetWare, NT.
<cough> <cough> Are you doing this on purpose?
> Recent consumer OSes such as Windows XP do use "protected memory"
> since the cost of GB of SDRAM is not prohibitive for consumers. I
MMUs have been around in the mainstream since i386, and systems such as
Linux have been using them (Linus' first box was an i386/SX 25). Redmond
has been shipping true (albeit lousy) multitasking systems since NT.
> know that several companies are working on a so-called HDD that is
> purely solid state and based on Flash-like RAM but I do not know how
> many months/years until it arrives. The other cause of system failures
It arrived several years ago. You can buy ~GByte of flash disk today. Some
of these devices use adapters for CF cards, but these are not designed for
r/w filesystems, and have a high rate of failure.
> is poorly written code that cause memory leaks or malicious code that
> tries to do memory buffer overflows. The response has been to try to
This is the only source of failures. However, failures of applications,
not OS. Unless you mean poorely written OSses, such as those coming from
Redmond.
There's a little userland application called crashme. It generates random
code and executes it. How long it can run before it brings the OS down is
a measure of OS's robustness. You might find it instrumental to obtain
that program, and run it on a selection of systems of your choice.
> prohibit both through pre-emptive multitasking in which the OS has the
> ability to override the program's instructions. Palladium by
More smoke. You _must_ be doing it on purpose.
> Microsoft, IBM, Intel and AMD, etc in Trusted Computing at
> www.trustedcomputing.org is supposedly a response to these problems
> esp. the malicious code.... I think it is more of a digital rights
Issue of trust is completely orthogonal to OS and app bugs.
> management (DRM) platform infrastructure that is disguised as a
> security initiative. Hopefully a market for non-Palladium PCs persists
> and a non-Palladium choice is still available after 2005 when these
> Palladium PCs are supposed to make it to market. I, for one, will
> save money and "stock up" on several PCs if I think that a
> non-Palladium PC choice will disappear.
There will be always alternatives, which will be somewhat more pricier
than your trash'o'day from Walmart.
> If any other technically inclined readers have additional insights
> into these issues, please post them. I just have an Associate's
> Degree in Networking - though I am now working on a Master's Degree in
> Computer Science. (I already have a non-tech Bachelor's Degree.) I
> know I have lots left to learn. - Bill.
Bill, you're quite confused about a number of issues. I doubt this list is
the right place to discuss this, though.
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