New hard disk architectures

  • Thread starter Thread starter YKhan
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Keith
Click to expand...

$1
Dear Mr Keith

$2
I sort of anticipated your reply based on experiences in previous exchanges.
Since in these sessions we have so far not reached a concensus, I propose we
try to agree on something less controversial.

$3
In the good political spirit, say we make a statement that we reached
agreement on that wasps are black with yellow stripes, or yellow with black
stripes.

$4
If you acknowledge that, then I will support you in the first statement and
admit the second is merely a different way of describing it.
This will, to all readers of c.s.i.p.h.c. show that we are making progress.

$5
You are then also given the last word.

$Motivation
Because it is this progress in mutual relations that will reduce flames, and
as you and all others know, flames are very dangerous now that some still
have the Christmas trees in the house.


$Summary and comon statement
See $3

Over to your delegation:
<start last word>

</end start last word>
 
By my calculations, you owe me $15 for the education.
Click to expand...
mm, try to think out of your box.
In politics if you 'owe' somebody, it could well be in the form of
nukes.

The '$' stands for paragraph.
Maybe over time we could reach concensus, but given that humans are mortal,
I can only repeat that the $3 wasp declaration would make you look better
in the eyes of the masses.
I will still support that $3.

Probably not needed to set an new date for a new bilateral until you have
worked out what to do with $3.
 
Jan said:
mm, try to think out of your box.
In politics if you 'owe' somebody, it could well be in the form of
nukes.

The '$' stands for paragraph.
Click to expand...

In your neighbourhood, perhaps. Yours is the first usage I have
ever seen of this. For the rest of us, classical techniques like
blank lines between paragraphs or indenting the first line of a
paragraph does the job quite nicely.
Maybe over time we could reach concensus, but given that humans are mortal,
I can only repeat that the $3 wasp declaration would make you look better
in the eyes of the masses.
I will still support that $3.

Probably not needed to set an new date for a new bilateral until you have
worked out what to do with $3.
Click to expand...

Bright guy that he is, I am sure that by now Keith has worked out
that with $3 he can buy a beer at most pubs.

I suggest you find another system for referring to a "third
paragraph" - most of us in Canada, the US, and a few other
countries are going to find it impossible to /not/ read $3 as
"three dollars".
 
Keith said:
You really don't think the drive can buffer more than
the OS - faster. A disk "cache" isn't. That's why it's
called a "buffer" and not a "cache". Read ahead/behind is
a win, write-buffering is a rather questionable strategy.
"Cacheing", I think not. You'll never *hit* that cache.
Click to expand...

This does raise a question: Modern OSes do considerable disk
caching (or buffering if you prefer). Should the strategy
or size change if the HD hw does more layout-aware buffering?
It has a *lot* to do with it. The processor just tells
the stupid DMA controller what to do and it does it.
Hardware is faster than software, dontchaknow.
Click to expand...

Very much agreed. On a Linux system, you can change the disk
access modes using `hdparm` and test it with same. The CPU is
_absolutely_ horrible at IO, often achieving only 1 MB/s.

-- Robert
 
Bright guy that he is, I am sure that by now Keith has worked out
that with $3 he can buy a beer at most pubs.
Click to expand...

Not here, convert it to Euro and rounding gives zero ;-)
I suggest you find another system for referring to a "third
paragraph" - most of us in Canada, the US, and a few other
countries are going to find it impossible to /not/ read $3 as
"three dollars".
Click to expand...
Irrelevant, US and Canada will be covered by glaciers.
The 'few other countries' will be South America (all communist) and Europe
(half commies).

Penguins will walk all over Redmond, and they need no beer.
 
Jan said:
Not here, convert it to Euro and rounding gives zero ;-)
Click to expand...

So Two=Zero in the EEC? I guess that explains why the French
and German economies are such a mess.
Irrelevant, US and Canada will be covered by glaciers.
The 'few other countries' will be South America (all communist) and Europe
(half commies).

Penguins will walk all over Redmond, and they need no beer.
Click to expand...

It will be polar bears, not penguins, and you should /never/ say
no to a thirsty polar bear.
 
So Two=Zero in the EEC? I guess that explains why the French
and German economies are such a mess.
Click to expand...
I merely extrapolated form when the dollar was still 4 Ducth guilders,
now it is less then 2 (less then one Euro), so it wil be below
zero i nan other 20 years, in fact you'd have to pay for people to
accept the old paper and it takes a lot to clean that up and keep the
environmet clean ;-)
It will be polar bears, not penguins, and you should /never/ say
no to a thirsty polar bear.
Click to expand...
Did you see that movie 'screamers' I think it was, you'd be surprised what
a teddy bear [like that] can do to earth.

(For the ones who did not see it, Teddy was a self replicating killer robot).

Penguins will wander all over the world, they need ice and fish.
Sure some would like North pole?
 
This does raise a question: Modern OSes do considerable disk
caching (or buffering if you prefer).
Click to expand...

OSs cache disk data, Drives buffer it. ;-)
Should the strategy or size change if the HD hw does more
layout-aware buffering?
Click to expand...

What gain?
Very much agreed. On a Linux system, you can change the disk
access modes using `hdparm` and test it with same. The CPU is
_absolutely_ horrible at IO, often achieving only 1 MB/s.
Click to expand...

It should be better than that, but it is still horrid compared to a
dedicated master. THe issue was interleaving though. While the
DMA controller is moving data the CPU can be figuring out what to
do with it[*]. The bits streaming off the platter become the
limiting factor.

[*] Remember, DOS was single-threaded.
 
I merely extrapolated form when the dollar was still 4 Ducth guilders,
now it is less then 2 (less then one Euro), so it wil be below
zero i nan other 20 years, in fact you'd have to pay for people to
accept the old paper and it takes a lot to clean that up and keep the
environmet clean ;-)
Click to expand...

Only a stupid marketeer would choose two data points (to his
advantage), lay a ruler across them, then extrapolate twenty years
into the future (saw someone do this with IBM revenues in 1980) to
prove his point. Only a pig-ignorant PHB would buy the argument.
You selling or buying? ...either way, you're not the sharpest
arrow in the quiver.
 
Keith said:
(e-mail address removed) says...

What gain?
Click to expand...

Extra track-to-track seeks: The OS has no idea of where the
actual track ends are (variable zones) due to remapping by the
HD controller. So when it does read-ahead, it may requires
an extra (potentially unneeded and expensive) track step.
It should be better than that, but it is still horrid
compared to a dedicated master.
Click to expand...

You are right, it is slightly better than that (DWORD IO).
I with thinking of only byte-wise IO:

# hdparm -d 0 /dev/hda
/dev/hda: setting using_dma to 0 (off)
# hdparm -tT /dev/hda
Timing buffer-cache reads: 488 MB in 2.01 seconds = 242.46 MB/sec
Timing buffered disk reads: 14 MB in 3.43 seconds = 4.08 MB/sec

# hdparm -d 1 /dev/hda
/dev/hda: setting using_dma to 1 (on)
# hdparm -tT /dev/hda
Timing buffer-cache reads: 504 MB in 2.01 seconds = 250.29 MB/sec
Timing buffered disk reads: 60 MB in 3.02 seconds = 19.85 MB/sec

THe issue was interleaving though. While the DMA controller is
moving data the CPU can be figuring out what to do with it[*].
Click to expand...

Or more likely, running other tasks/threads.
The bits streaming off the platter become the limiting factor.
Click to expand...

And have been for quite some time (386?)

-- Robert
 
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mm, try to think out of your box.
In politics if you 'owe' somebody, it could well be in the form of
nukes.

The '$' stands for paragraph.
Click to expand...

I think this is the symbol you meant to use (hopefully it'll work):

¶

"$" is a currency symbol, not a paragraph marker.

_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( http://alfter.us/ Top-posting!
\_^_/ rm -rf /bin/laden >What's the most annoying thing on Usenet?

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