The Cost of a Big Cache
In response to my reply to More from
Andrew Prosnik, Ed Hurtley explains:
Okay, most of my complaints about Andrew Prosnik's comments have
been addressed. Now I have a comment addressed at your comment.
:-)
Any CPU would benefit from bigger caches. Why Motorola, Intel, AMD,
and IBM don't just throw a 1-2 MB level 2 cache right on the CPU is
beyond me. Sure, it would make for a more costly "pro" CPU, but imagine
the extra efficiency. This would also help demonstrate the full
potential of CPU designs, since they would be less limited by their
connection to the motherboard.
Why not? Because die space is hideously expensive. For large caches,
there are two options: Put it in the same die (same piece of silicon)
as the main processor core, or put it on separate chips. With most
"consumer" processors, the former is used. The Pentium 4 has 512 KB of
level 2 cache in it's main core. The Athlon XP has just been upgraded
from 256 KB to 512, with the 512 KB models just now hitting the
shelves. Even Motorola is in on this, with the PowerPC 7455 having 256
KB of level 2 cache.
But the larger you make the piece of silicon, the more expensive it
has to be (as each "wafer" has a fixed cost, so the fewer processors
you can put on a single wafer, the more you have to charge). So putting
tremendously large L2 caches in the same die as the processor core gets
expensive fast. Intel is planning on releasing two "consumer" cores
with 1 MB of L2 cache soon, the Pentium-M (Banias/Centrino) mobile
processor and the upcoming "Prescott" core of the Pentium 4. This can
largely be done by decreasing the "process technology" used, or the
micron size of the gates. (Most current consumer processors use a .13
micron size, with Intel's "Prescott" scheduled to be the first .09
micron processor.)
As for putting the L2 cache on a separate chip, again, there are two
ways of doing it. One is to use commodity chips and just put them very
close to the processor core, such as what Apple does with the G4's L3
cache (before the G4 had an onboard L2 cache, they did the same thing
for the L2 cache). Intel also did this with their Pentium II and early
Pentium III chips, putting the core and the L2 chips in one processor
"package." AMD followed suit with their first Athlons.
At that time, trying to put an L2 cache in the main processor core
was considered "too expensive" by everyone, including Intel. So Intel
made high-performance models (Pentium Pro, Pentium II Xeon, and early
Pentium III Xeons) by making their own L2 cache chips, making them very
fast, and putting them closer to the core than had usually been done.
Even today, Intel's Itanium and Itanium 2 use this approach.
I have friends who still work at Intel, and one got me a picture of
the inside of the Itanium's package. (See http://www.hurtley.org/itanium.jpg,
sorry, it's pretty big.) The "large" chip is the main core; the four
side chips are the L2 cache. This is what the Pentium Pro and the
Pentium II Xeon basically looked like. You can see that the cache takes
up more silicon than the core! That is the real reason that the
Itaniums are expensive. That is also why the Xeon versions of the
Pentium II cost $6000, when the same speed 'normal' Pentium II cost
$800.
Intel could probably produce a sub-$800 Itanium-based processor if
they put very little L2 cache in it. (The L2 cache is also the biggest
power draw in an Itanium.)
Slow memory is cheap. Fast memory is expensive. If anything can
deep six the PowerPC 970 as the heart of future Macs, it's the 970's
insistence on accessing memory at half CPU speed. Fortunately the 970
design can interleave two memory banks, but that still means 625 MHz
memory will be necessary to support the 2.5 GHz PPC 970 - and it will
only get worse as the CPU gets faster.
One way to make a cheaper computer is to use slower memory, but then
the CPU has to wait even longer when it accesses motherboard memory. To
minimize this, we have level 1, level 2, and level 3 caches. L1 caches
have always been quite small and right on the CPU. Until a few years
ago, L2 caches were separate chips. On G3 Macs, they were usually 256
KB or 512 KB and often ran at 40-50% of CPU speed.
In the past few years, it has become common to put a smaller L2 cache
(256 KB has been common until just recently) on the CPU die, allowing
it to run at the same speed as the CPU. The theory is that the faster
speed would help offset the smaller size.
And that also made L3 caches important, since the smaller L2 cache made
it that much more likely that a call wouldn't be within the cache. With
a 1 MB or 2 MB L2 cache running at half CPU speed - just like
the L2 caches of a few years ago - there's a much smaller performance
penalty for a miss, at least when that data is in the L3 cache.
By doubling the 512 KB L2 cache that's becoming common on today's
higher-end CPUs, the number of CPUs per wafer would be reduced, and
this might increase the cost per CPU by 50%. On the other hand, not
only would this further reduce the odds of a L2 cache miss, but it
could also eliminate the need for the L3 cache sitting between the CPU
and motherboard memory.
It would still be more expensive, but with today's multithreading,
multitasking operating systems, the benefits of a bigger cache could
justify it for high-end applications.
The other side of the equation, which IBM is throttling with the PPC
970, is moving beyond today's "pedestrian" 133-266 MHz busses to
something very, very fast where the penalty of a cache hit will be
significantly minimized.
Things were so much less complex when computers didn't need wait
states, CPUs didn't need caches, and the whole machine had less memory
than today's level 3 caches. On the other hand, who really wants to go
back to the days of 8 MHz CPUs and 1-bit video?
Haxies and CPU Load
Last Monday, Ken Arroyo warned me
against using Unsanity "haxies" on my computer. In response to my
questions, he explains:
Sorry for being non specific, I've had no trouble with Silk
whatsoever with Silk or WindowShade, but specially if you have an older
Mac, Cee Pee You, Xounds, and Labels really slow down your computer. I
guess its the fact that they run monitors all the time to do their work
but I have seen them with top using 30-40% of my processor (800 MHz
PowerBook).
Thanks for the clarification. I'm currently running Memory Usage Getter on my
400 MHz TiBook and displaying processes by CPU load. The frustrating
thing is that Cee Pee You doesn't show up as an active process, yet
it's displaying the CPU load. That's gotta use some cycles!
Speaking of Labels, I wish Apple
had left them in OS X. I've been using them to label site content
- one color for 1997 articles, another for 1998, and so on. I'll have
to give this one a try to restore Yet Another Lost Classic Mac OS
Feature.
As for Xounds, I never did understand the point of adding sound to a
graphical user interface.
VisualPage
Symantec used to make a great simple program called "Visual Page"
that they abandoned the Mac version of after the 1.1.1 version. However
a fully functional trial version can still be downloaded from
Tucows:
<http://providenet.mac.tucows.com/preview/206162.html>
I tried Home Page, Page Mill, and Visual Page and decided I liked it
best. I believe it behaves a bit better than Home Page as far as the
code it generates. I don't know if it will work under Classic or even
OS 9 for that matter but it works great under OS 8.6. I don't know if
you can even buy retail copy any longer, but I imagine if you like it
you could find a copy on
eBay. If not the trial version, continues working past the 30 day
time period.
I'll give it a look.
Avoid MyRealBox
Charles W. Moore recommended MyRealBox as one of several free email
service providers worth investigating in Free and Cheap .mac Alternatives. E McCan
sends these words of warning:
Don't have C. Moore's info, and I think he's the one that did the
article....
In any case, in one of the previous free POP mail articles, he
mentioned MyRealBox (http://www.myrealbox.com). I've used it
for a while, and I've got to say - avoid it.
- It's a test site. Okay, I could deal with that for a while. But
uptime's lousy, as are some other things that have been happening.
- They are lousy at communicating . . . well, anything.
They recently started blocking Yahoo! groups, saying they're "a source
of spam." (Having been on them for quite some time, running 6 of them
and being a member of 27 others, that's false.) They didn't send email
to anyone mentioning this, though . . . yes, it's in their
FAQ, but I thought it was a problem with Yahoo because of the bouncing
messages. Nope. Started 10 Feb. Tried all Yahoo's troubleshooting (not
that they're all that great on helping) but no go. Just happened to
check the FAQ, since they're updating their virus software on
MyRealBox, and I thought that might be the problem. Thanks for
the notice.
- Odd behavior with email clients - Eudora doesn't like them unless
you manually add their certificate (again . . . buried in
their site). And it tends to hang on receiving (buried in their site
again - change a network setting.) None of which is easy to find
right away, or intuitive to figure out.
MyRealBox might be free, but it's just not worth it. Scratch it from
the list.
There's an email link to Moore at the top of each and every article
he writes, and it looks like you
corresponded with him in the past explaining how to get MyRealBox
to work with Yahoo groups.
But, like they say, things are worth what you pay for them - and only
rarely more than that. Moore mentions that it is a demonstration site
in his article, as well as occasional downtime. I'd hesitate to use a
service with enough downtime that someone needs to mention it....
And at least MyRealBox is putting information on their site about what
they're blocking, how to make Eudora work, etc. A lot of email
providers, free and otherwise, don't provide any indication what may be
blocked as spam or how to configure your email client properly.
Not bad for free, but I'd prefer a service that's a bit more up front
about changes. (I wish Apple had been the least bit up front when they
decided to block our mailing lists as probable spam on .mac. That's a
service I pay to use....)
Try Freeway Express
Tony Crooks recommends looking into Freeway Express as an
alternative to Claris Home Page:
What about SoftPress's Freeway Express. In the UK it costs
£49, so about $75-80. Not quite a full version of Freeway 3.5.5
but not far short either. And if you know how to use DTP then Freeway
is an easy option. As far as I know its only true weakness is that
because it generates the HTML after you have done the site design, it
isn't too good at importing web pages. But that isn't too much of a
problem for most people. Visit www.softpress.com/express for
details.
Based on a lot of positive feedback, I did try Freeway a few years
ago. As someone with thousands of pages on his website, it's simply
impossible to use a design program that can't import my existing
pages.
More on Switching from Macs to Windows
Responding to my reply to his letter on Switching from Mac to Windows, Peter Breis
comments:
Sounds like our thoughts are not that far apart s:-)
I have my W2k Pro workstation, and as impressed as I am by its speed
and general usability, I am still most of the time back here on my G4
with OS X 10.2.4.
Truth to tell, the W2k workstation was not that easy to set up,
although I put that down to my lack of familiarity with the OS and the
fact I have customised it extensively. I look forward to the end of the
process where I just use it to get my work done.
Doesn't do Apple much good, though, because I can't see myself
buying another Mac in a rush, especially now I have invested in the W2k
machine.
Yes, I have been following the MacInTouch thread and find it
interesting that there is little comment on what I find the major
shortcomings of OS X.
You have said in the last couple of paragraphs eloquently what I
have felt for years. Truly it took a lot for me to switch, and I did it
with great sadness.
Time will tell. Now we'll see if Microsoft can drive you
away....
Finding a CD-RW Driver
In response to Ib Roslund's quest for
a driver for his CD burner, Eric Matthieu writes:
Another option for Ib Roslund's quest for a driver?
http://www.macdrivermuseum.com/disk.shtml
Ah, now there's a good suggestion. Not knowing what brand of drive
we're dealing with, I have no idea if any of these will work.
Drive Setup to Clear a Drive
After reading Wiping a Hard Drive
Completely, Scott Earleywine suggests:
Can't you use Drive Setup to 'write all zeros' and do a low level
format to (somewhat) wipe a HDD?
Drive Setup comes with OS, so there wouldn't be a need to purchase
Norton, right?
Sure, make me run down to the basement, find Mac running the
classic Mac OS, and find out....
You're right. It's listed as an Initialization Option in one of the
menus. Much cheaper than Norton. Thanks for the tip!
Another Way to Wipe a Drive
In response to the same article, Gyger writes:
I was reading the latest LEM Mailbag, and was interested in the
section on completely clearing a hard drive. For what it's worth,
there's also a freeware tool for this purpose for those who don't have
Norton Utilities. Burn is available from most download sites (such as
www.tucows.com) and can
irretrievably delete both individual files, as well as zeroing out all
the free space on a hard disk. Burn also comes with a variety of
security options including multiple wiping passes, and the option to
write random junk over the hard disk rather than just zeros or ones.
All in all a pretty good tool.
I might point out that these such tools also exist for the PC and
probably Linux as well. On my Windows 95 machine, I use Mutilate which
is a shareware app.
I found Burn
2.5 thanks to a link on Tucows. The classic application
requires System 7 or later, can overwrite a file numerous times, can
wipe all free space on a drive, and is free.
Printing from an Older Mac
After reading Printing from an LC
475, Gerhard suggests:
My solutions/suggestions about printing with an old LC:
As you already were suggesting, I am using an 1998 Epson 740, which
was originally purchased for a Bondi blue iMac (Rev. B). This device
can simultaneously handle three connections: USB (my iBook is
connected to it), PC-style parallel port (free), and Mac-style serial
port, which is used by my LC 475.
You will need a serial printer driver. I used the one that came with
the original installation CD. (The first time since 5 years this CD was
useful, since it lacked the drivers for the USB port, which was the
feature this printer was bought for.) If you are low on memory, you may
want to disable background printing and/or color printing as well. Both
functions are consuming many megabytes of memory.
If you pick a used Epson 740, be careful to find a good one. Since
the printing heads are not exchanged when swapping the ink cartridge,
it may become subject to wear and clogging. This is especially true if
the printer was not used for a very long time or stored without an ink
cartridge. If you find a good one, you will be rewarded with the lowest
printing costs. Fully reliable third party ink cartridges are sold at
prices as low as 25% of the original Epson ones, resulting in a
printing price of 5 cents per page or lower!
You may want to check Epson's site for a Mac printing special. Once
I even found a table there listing all Mac serial port equipped devices
- very useful purchase help.
Other options:
Buy any Hewlett Packard DeskWriter. Since HP's DeskWriters are
nearly indestructible, old ones will work like new. The only issue I
ever heard of (and experienced myself) is that the paper rollers my
start to slide over the paper. In most cases you just have to clean
them with a piece of cloth (rough linen works best) wetted with water
and very little of dish washing soap. There are a lot of help tips
available on the net regarding this issue.
Buy an old LaserWriter. Especially on older/slower Macs it is a good
idea to leave much of the computing work needed for printing to the
printer. Postscript capable LaserWriters will take a lot of work load
from the little computers and will produce nice, clean output.
Good luck!
Good advice, especially on the Epson with USB and Mac serial
support. I don't know if anyone besides Epson ever did that.
I've had mixed results with HP. My first DeskJet, a 500, was a tank. I
bought it in my DOS days, later used it with my Mac, later sent it to
work with my wife, later gave it to my brother, who was still using it
last I heard. My second HP was a Color DeskWriter. It lasted about 3
years. My third as an Apple StyleWriter 4500, which was a repackaged
version of some DeskWriter model. Piece of crap. CompUSA had at it.
It's gathering dust in my basement.
HP inkjet printer quality has fallen through the floor on low-cost
printers. Avoid them at all costs. HP makes great laser printers (I
have one), and their higher-cost DeskJets have a good reputation, but
avoid any printer that costs less than 3-4x the cost of a set of ink
cartridges.
An old LaserWriter is another good option, and some of them (I think
the LW IIf and IIg, as well as almost all of the newer ones) include
LocalTalk and ethernet support. They are mostly tanks that will last
about forever, and a single toner cartridge can last an average user
well over a year.
Well, that gets me up to Thursday in my quest to catch up on email.
More on Tuesday or Wednesday.
Dan Knight has been publishing Low
End Mac since April 1997. Mailbag columns come from email responses to his Mac Musings, Mac Daniel, Online Tech Journal, and other columns on the site.
