Unexpected Results with Fast Ethernet
Adrian Abraham writes:
Your explanation on why Fast Ethernet would not be advantageous on a
G3 makes perfect sense to me, except that in practice this is just not
so.
I have a 7300 and a
G3 networked via a 10
Mbps hub to my Pentium III that runs a software router and has 56 kbps
dialup. I noticed that Web pages loaded far faster on the 7300 that had
a 3Com 10/100 NIC [Network Interface Card] than the G3 that used the
built in 10 Mbps port. That was is in OS 9.
Unfortunately, I could not get the 3Com card to work under OS X
on the G3 but lucked when someone advertised the sale of Apple branded
10/100 Mbps NICs on the swap list. I
bought one, and it has made a significant improvement to surfing speed
on the G3 in OS X, ready for when I go broadband :)
Another major difference is that OS X Mail does not time out at
all when it used to do so regularly- this is probably due to trying to
share a 56 kbps dialup via 10 Mbps hardware.
BTW, I just dropped that card in, and it worked straight away
:)
My guess is that a 10/100 Mbps NIC is far more efficient at 10 Mbps
than a straight 10 Mbps NIC- if that makes any sense to you
:)
Sadly, this just adds to reasons not to spend money on a G3: You
need yet another slot to improve networking :(
Thanks for the great site!
I must admit that with seven years of articles on this website -
thousands of them- I don't know just which one you're referring to. Nor
can I understand why you'd find Internet access speed any different on
over fast ethernet than on plain old 10 Mbps ethernet when you're
connected with a 56k modem to begin with.
That said, the AAUI ethernet ports built into Quadras and Power Macs is
problematic when used with 10/100 hardware. At my last job, we had so
many problems with these machines that we ended up either segregating
them to their own 10Base-T hubs or put in Farallon 10/100 ethernet
cards.
It was the only way to keep the network stable. So I don't think
there's anything inherently more efficient about using a 10/100 NIC on
a 10 Mbps network, only a real problem with Apple's ethernet ports on
10/100 hubs and switches.
I'm really surprised that you're running into this kind of problem at
all on a 10 Mbps hub connecting just three computers. I've never seen
problems like this without a 10/100 hub or switch and several older
Macs on the network.
Happy with Mozilla HTML Editor
Responding to my reply to HTML
programs, E McCan writes:
Don't even get me started on the abominable HTML that Microsoft Word puts
out- it makes Microsoft Frontpage look reasonable. Home Page may be
outdated, but at least it's not stupid.
The HTML editor in Mozilla may come closest to doing what you want. Try
it. I didn't like it, but then I don't hand code, either. The Mozilla
editor at the very least didn't seem to change code on the page it
opened. And it's free.
You know, I've had it sitting here for a while and haven't tried it
(shades of problems with the old "Netscape Gold" editor.)
My only problem doing a test page (I have a boilerplate I use for my
site reviews at http://airmodeller.tripod.com) is
that it wouldn't let me get beyond the table I use for basic kit info.
Just a period or a "Replace me" fixes it, and it does seem to
generate clean code.
Thanks for the suggestion. Given that all my text styles are in
style sheets, it'll make using it easier, too.
Low Level Drive Format Danger
In response to the suggestion to use
Drive Setup to zero a hard drive, David Walker notes:
The reason Apple took that option out of Drive Setup is the fact
that IDE drives aren't meant to be low level formatted except once at
the factory.
If I recall correctly Mac users were using the option and ruining
their IDE hard drives.
SCSI drives can be low level formatted repeatedly with no ill
effects.
If I recall correctly, and it's been several years since this issue
first came up, it's not actually possible to low level format an IDE
drive with Drive Setup, and that's the reason the option no longer
shows up with IDE drives.
What Drive Setup does do is reformat the drive, and I believe it will
write zeros to every byte in every sector, even though it doesn't do a
low level format. However, it's my understanding that this is a more
thorough clearing of the hard drive than simply erasing it. It should
provide adequate security against most prying eyes.
B&W G3 Addendum
After reading my praise of the blue
& white Power Mac G3 as a best buy, John Christie adds one more
bit of information:
I noticed in your B&W G3 specs you miss an important option.
There was an education version that ran for awhile. It was designed to
be much cheaper and allow video capture. I have used, sold, and
serviced several of these. The primary difference is that they came
with a Rage Pro video card that had video capture. You might want to
include that in the profile so that folks know they don't all come with
a Rage 128.
That's news to me. I wasn't aware that Apple offered different
hardware configurations to the education market. I'll update the
b&w G3 profile to reflect this.
I'm still waiting for ATI to release an All-in-Wonder
Radeon card for today's Macs. Video input and output, a television
tuner- could reduce the need for Mac users to spend money on TiVo or
Replay TV. Too bad it's a Windows only card.
Four PCI Slots?
In response to my thoughts on the
blue & white Power Mac G3, Al Shep comments:
You will probably get a few emails with this nitpick, but oh
well.
The four PCI slot thing is not a real bonus unless you run your
B&W headless. Now as a headless server, I see the 4th slot being a
real issue, especially if you put something cool in the 66 MHz PCI
slot, other than a video card of course.
Great piece, I love my B&W and really appreciate your singing
its praises.
I do explain that you really need to have a video card in one slot-
and because it's quite common to add a better video card to the beige
G3, by comparison the b&w G3 does have one more available expansion
slot.
Detail on pre-G3 PCI Power Macs
After reading The Value and
Limitations of the Beige G3, Gary Shelton comments:
Re: The Value and Limitations of the Beige G3, I offer only one
correction, which you need not publish. The system bus on the PCI Power
Macs (7500-9600) is anywhere from 40-60 MHz, but the memory bus on
these models runs much slower. I believe the memory bus speed is around
15 MHz, or thereabouts. The Beige G3 was the first Power Mac to use
SDRAM (where the memory bus and the processor bus run at the same clock
speed).
The system bus on the PCI Power Macs was actually set by the CPU
card. It could go as low as 40 MHz and was officially rated at 50 MHz
tops, although a few will support speeds of 51-52 MHz. Only Power
Computing managed to over design the bus enough to support a 60 MHz
system bus.
These computers supported a level 2 (L2) cache that could feed data to
the CPU at the full speed of the system bus, which helped make up for
the relatively slow motherboard memory. One further advantage of the G3
is that the L2 cache was on the CPU module, so it was not limited by
the system bus. In fact, by running at half CPU speed (116.7 MHz on the
entry level G3), the L2 cache was roughly 2-3x faster than that on the
previous generation of Power Macs.
That's just one more way the Power Mac G3s were a big improvement over
the models that came before them.
AirPort for Older iMacs
Looking for a way to use wireless networking with an older iMac,
Owen Strawn writes:
Dan, can you tell me where I can get info on what options are
available for using AirPort on a tray-load iMac? I am sure there must
have been a column addressing this on LEM, but I can't seem to find
anything using the search function.
My wife wants me to move her tangerine iMac to the bedroom, and I am
at my wit's end trying to figure out how to string ethernet cable that
far through a finished ceiling, so I am thinking it may finally be time
to look into wireless networking.
You have two wireless options- you can connect via USB or you can
connect via ethernet. Either way you'll need a wireless hub plus an
access point for the iMac.
I'm not familiar with the USB access points, but I've heard they're out
there. The bandwidth of USB is a bit lower than that of AirPort, but
then most Internet connections are slower than either.
The alternative is to skip plain old AirPort entirely and step up to
802.11g networking, which is AirPort Extreme in Apple's version. As
noted in Extreme Wireless for Older
Macs, there are four other manufacturers of 802.11g hardware, and
some of them provide Mac support. D-Link is already partnered with
Apple on their Bluetooth adapter, and Belkin has promised drivers for
the classic Mac OS, not just OS X.
These third-party solutions are a lot less expensive than Apple's, and
all of them make 802.11g access points that can connect to the ethernet
port on your older iMac- or any Mac with an ethernet port, for that
matter.
Maximum theoretical throughput is 54 Mbps, about half the 100 Mbps
rating of the iMac's ethernet port, but you'll probably only see 26-28
Mbps in the real world when moving files between machines locally- and
your Internet connection is much slower than that.
Even shopping around, you're probably looking at US$250-300 for a hub
and access point.
Getting the Numbers Right
In 1987: Apple Introduces the Mac II
and SE, I wrote:
SCSI was twice as fast as on the SE, offering performance to rival
today's highest speed USB 1.1 devices. As with the SE, it really
benefits from a newer hard drive- something built since 1989 or so can
take full advantage of the Mac II's SCSI bus.
In response, Steven Hunter writes:
USB 1.1 is 12 Mbits/sec (1.25 Mbytes/sec) while the SCSI in the Mac
II was 10 Mbytes/sec, meaning it's 8 times faster than USB 1.1.
:)
USB 1.1 is indeed rated at a maximum throughput of 12 Mbps,
although on the Mac it rarely reaches 60% of that level (and things
aren't a whole lot better on the Windows side- maybe 75% tops).
SCSI-2, the standard used on the Mac II and SE, has a rated maximum
throughput of 5 Mbps on an 8-bit bus, which is what these Macs used,
not 10 Mbps as you state. (See our tech piece on SCSI Throughput for more details.)
Theory and practice diverge. In the real world, the SE has a maximum SCSI throughput
of 5,248 kbps, which is a bit less than half the theoretical maximum
for USB 1.1. The Mac II has a
maximum throughput of 11,200 kbps, very nearly the USB 1.1 maximum and
better than any USB device manages in the real world.
These limitations were imposed by the hardware Apple chose; it didn't
support the full speed allowed under the SCSI-2 specification. It
wasn't until the Quadra era that Apple offered any computers with a
SCSI bus capable of reaching 5 MBps on an 8-bit SCSI bus.
Correction on Mac Plus SCSI
After reading 1987: Apple Introduces
the Mac II and SE, Matthew Sparby states:
A quick correction regarding your article about the introduction of
the Mac SE and Mac II.
You have misstated the speeds of the SCSI ports on the early Macs.
SCSI speeds are measured in megaBYTES per second as opposed to megaBITS
per second. The original SCSI port on the Mac Plus was 2.5
megabytes/second which is faster than USB 1.1 which tops out at 12
megabits/second or 1.5 megabytes/second.
There's absolutely nothing wrong with converting MB/sec to Mb/sec
to help readers understand the difference between SCSI (usually
measurerd in MB/sec) and USB 1.1 (specified in Mbps). That's what we
did.
For the record, Apple's officially
stated maximum SCSI throughput of the Plus, SE, and Mac II is
1.25 MB/sec. This is despite the fact that the SE is at least 50%
faster than the Plus, and the Mac II is about twice as fast as the
SE.
The numbers on our profiles covering the Plus (2,104 kbps), SE (5,248 kbps), and Mac II (11,200 kbps) come from an old issue
of Macworld or MacUser, where they are definitely states as
megabits per second, not megabytes. I rounded these to Mbps in
my article so they could be more readily compared with USB 1.1.
This again points up the discrepancy between theoretical and real world
throughput. Although Apple rates all three models at 1.25 MB/sec, the
Plus only achieves 0.263 MB/sec, the SE just 0.656 MB/sec, and the Mac
II exceeds spec at 1.4 MB/sec.
None of these come close to the 2.5 MB/sec figure you state or the
official SCSI-2 maximum of 5 MB/sec. That's what happens in the real
world, where USB 1.1 never reaches 12 Mbps either.
ADB on All Blue & White G3s?
It should be noted that only the Rev.1 Blue and Whites have
ADB. Rev 2's eliminated this, I believe. I own a Rev. 1, and I remember
how quickly the Rev. 2's came out. Mac Addict had a blurb on telling
the difference, having to do with rear port orientation. I believe the
Rev. 2's had two separate USB channels, rather than one channel with
two ports as in the Rev. 1.
Every source I've checked- including the AppleCare
Knowledge Base- states that the b&w G3 has an ADB port. I
can't find any source that says otherwise.
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.
