Low End Mac Reader Specials

TypeStyler For Mac OS X is Now Shipping! Download The Free Fully Functional 60 Day Tryout at www.typestyler.com

Don't install Parallels to play poker online! Poker Mac will show you how to download and install a native Mac poker application such as Full Tilt Poker Mac.

Laptop Hardware Provided by TechRestore - Overnight Mac & iPod Repairs.

Compare products like desktop computers, apple laptops, apple macs, and LCD Monitors side by side! All the information and reviews to make the best purchasing decision for new mobile phones, sat nav systems, or MP3 players. The Ciao online shopping community makes searching products easy for you.

We Still Need SCSI

Andrew W. Hill - 2001.08.31

My Turn is Low End Mac's column for reader-submitted articles. It's your turn to share your thoughts on all things Mac (or iPhone, iPod, etc.) and write for the Mac web. Email your submission to Dan Knight .

Let's start with the Megahertz Myth today. You've gotta have the fastest processor possible, right? Sure, we know that an 867 MHz G4 is faster than a 1.7 GHz Pentium 4. And as long as you have the fastest Mac around, you're golden, right?

There is always a bottleneck when talking about performance. The time it takes you to get to work is one example. The bottleneck is that place on the freeway just before the old bridge where the road goes from five lanes down to three.

On your G4, is the CPU the bottleneck? At 867 MHz, it's the fastest part of the computer!

How about the RAM. Obviously, we have level two and level three cache because the motherboard RAM is so slow. Maybe we should start using DDR (Double Data Rate) SDRAM in Macs to increase the speed. It takes the computer 7 nanoseconds or so to access RAM. What a tremendously long time!

Or maybe access time isn't what we should be looking at. PC133 is 64 bits wide and runs at 133 MHz; that means 1064 MBps throughput. 1.04 gigabytes per second? If you have enough hard disk space to make that an issue, you may also own BMW.

That gives me an idea - how about the hard drive?

Lets face it, the hard drive is the slowest part of a personal computer. With access times around 8 milliseconds, it takes the computer 1000 times longer to access the hard disk than RAM. While the G4 ships with ATA66 and boasts of 66 MBps throughput, it rarely breaks 35-40 MBps.

Maybe we should ship the next G4 with ATA100 disks? Maybe even ATA133 disks? There are rumors that the current G4s are capable of running at those speeds, but Apple has nothing to say on this.

I have a much better idea: SCSI.

Why SCSI? Ultra320 SCSI is almost ready for consumer use. That's a potential 320 megabytes per second. I realize that today's drives aren't quite capable of those speeds, but 15,000 rpm drives are available with access times under 4 milliseconds.

"SCSI is so expensive," you scream. "SCSI is just for digital video people and graphic designers. Don't you ever read PC World?"

No, I do not read PC World. This is because I think different(ly).

Once upon a time disk reads and writes were done a lot less than they are now. I remember getting taught to save my documents every 15 minutes, which seemed like a ludicrously short period of time. Now I save every three or four minutes. Saving data on floppy disks took forever, so it wasn't done much. On the Windows side of things, multitasking wasn't even available until 1995 (at least not in any meaningful way), so you would usually just save what you were working on.

Things have changed with the Web.

Every time you look at a Web page, your computer accesses your hard drive. It saves data in a cache, because your hard drive is faster than you Web connection. If you use an instant messaging program, they probably save logs and history files. Every time you get a new email, your disk is active. With multitasking, sometimes you can be opening one program while your email is downloading and someone is sending you an ICQ message. This means a lot of disk access, akin to rush hour at the aforementioned bridge.

And that's exactly where SCSI beats IDE. SCSI drives are intelligent, meaning they can process an instruction and let the CPU get back to work. IDE drives require a lot more CPU time, which isn't a big problem if you're running one task at a time, but becomes a problem when you run a multitasking operating system like Mac OS X. The intelligent SCSI bus even lets devices communicate directly, so one drive can send data to another drive without tying up the CPU.

Graphic designers and digital video experts have relied on SCSI for the speed they need, but disk usage in other areas has increased. With more demands on the drive, there are more reasons than ever to use SCSI.

The processor in my Blue G3/450 is good enough for me. Sure, a G4 would be nice, but I would rather have a few 10,000 rpm Ultra2Wide SCSI drives than an 867 MHz G4 processor.

Andrew W. Hill (a.k.a. Aqua) has been using Macintosh computers since 1987 and maintains that the Mac SE is the perfect Macintosh, superior to all - including the Color Classic. He is on the verge of being evicted from the family home due to its infestation of Macs (last count: about 50). Andrew is attempting to pay his way through college at UC Santa Cruz with freelance Web design and Mac tech support.

SCSI & IDE: Overview and Comparison, Markus Westergren & Mattias Sandgren, 1998 (revised). Good tech overview. Summary: With a single device, SCSI vs. IDE makes no real difference. However, SCSI is superior when multiple devices are used because "The ATA devices lacks the intelligence to perform command queuing like their SCSI counterparts...."
IDE vs. SCSI, David Risley, PC Mechanic, 2001.03.25. "SCSI is a smarter bus than IDE. There are many steps in the SCSI data transfer. But, on OSes that allow multitasking, or if you often use several programs at once, the SCSI drive is a better choice because this extra intelligence of the SCSI bus is used.
"The performance overhead of SCSI over IDE comes from structure of the bus, not the drive. The nature of the SCSI bus allows it much better performance when doing data hungry tasks such as multi-tasking. The SCSI bus controller is capable of controlling the drives without any work by the processor."
IDE or SCSI Disk, H. Gilbert, Introduction to PC Hardware, 1998 (revised). "SCSI is worth the extra cost in a Server. EIDE supports two separate I/O operations to two disks (on the two different interface cables). SCSI allows all of the disk devices to be active simultaneously."

Share your perspective on the Mac by emailing with "My Turn" as your subject.

Recent My Turn articles

Using Low End Macs for Internet Radio, 08.18. When the local public radio station moved classical music to HD radio, it was time to find another way to listen. An old iMac with iTunes solved the problem.
'That's Not a Computer', 07.30. Salvaging a broken PowerBook by turning it into a desktop computer.
Upgrading a Digital Audio G4 to work better in Leopard, 06.02. In its original configuration, the dual 533 MHz Power Mac G4 was slow with Mac OS X 10.5, but add the right upgrades, and it runs Leopard quite nicely.
My 4 favorite PowerBooks, 05.28. The PowerBook 150 has a big screen for a vintage PowerBook, the 165c has color, the 100 is diminutive, and Lombard has USB and a great keyboard.
More in the My Turn index.

Links for the Day

Mac of the Day: 17" MacBook Pro Core Duo, Apr. 2006 - The top-end MacBook Pro includes a 1680 x 1050, 2.16 GHz Core Duo CPU, and supports Apple 30" Cinema Display.
Group of the Day: G4 List is for those using Power Mac G4s or G4 upgrades.
Support Low End Mac

Recent Content on Low End Mac

Pismo WiFi Networking Issue Finally Solved?, Charles W. Moore, Miscellaneous Ramblings, 11.24. It turns out the problems wasn't the Pismo, the Buffalo WiFi card, or Mac OS X 10.4. It was the Wireless G router - Linksys to the rescue!
Mini VGA to S-video Adapter a No Go for eMacs, Dan Bashur, Apple, Tech, and Gaming, 11.24. You might think that Apple's Mini VGA S-video adapter is a cheap way to connect your eMac or G4 iMac to your TV. You would be wrong.
Google Calendar with iPhone or iTouch Is Great for Scheduling, John Hatchett, Recycled Computing, 11.24. Web-based Google Calendar allows access and updates from any computing platform, including Mac, Windows, Linux, and iPhone OS.
Why Spaces is My Favorite Leopard (and Snow Leopard) Feature, Charles W. Moore, Miscellaneous Ramblings, 11.23. Spaces, a feature introduced with OS X 10.5, is like having several monitors on your Mac without the cost and space of using multiple displays.
i5 iMac Benchmarked, Mac mini 'Shouldn't Be Overlooked', Twitter Client for Classic Mac OS, and More, Mac News Review, 11.20. Also why Apple leaves the low end to others, 10.6.2 fixes video playback problem in 27" iMac, 3D Leopard and Snow Leopard performance, and more.
Apple's Tablet an End Run Beyond Netbooks, Frank Fox, Stop the Noiz, 11.20. Whatever Apple has planned will leverage existing technologies while going beyond what its competitors can offer.
Apple #4 in Reliability, Apple Tablet a Gadget for All?, HP's i7 Notebook Outdoes Mac Rivals, and More, The 'Book Review, 11.20. Also Flash 10.1 improves video on Hackintosh netbooks, thin-and-light notebooks impress, Windows XP finally on the way out, and more.
NASA Chemical Sensor for iPhone, Smartphone Death Match, iPhone Earrings, and More, Ian R Campbell, 11.20. Also mobile phone dangers, new apps, GPS solution for iPod touch, new iPod and iPhone cases, and more.
More links in our archive.

Recent Deals

Best iPod nano Deals, 11.25. Refurb 8 GB 4G nano, $99; new, $126; refurb 16 GB, $129; new, $150; new 5G/8 GB, $134.60; 16 GB, $161.12. Shipping included.
Best Classic Mac OS Deals, 11.25. System 6.0.8 floppies, $10; 7.1, $12; 7.5, $20; 7.6 $13; 8.1, $11; 8.5, $20; 8.6, $90; 9.0, $20; 9.2.2, $30.
Best 15" PowerBook G4 Deals, 11.25. Used 1 GHz Combo, $400; 1.5 GHz SuperDrive, $449; 1.67 GHz hi-res, $600.
Best G4 iMac Deals, 11.24. Used 15" 700 MHz CD-RW, $150; 800 MHz Combo, $229; 1 GHz, $289; 17" 1.25 GHz, $200; 20" 1.25 GHz, $509.
Best MacBook Air Deals, 11.24. Used from $899; refurb from $1,099; new 1.6 GHz/120 HD, $1,150 after rebate; 1.8/64 SSD, $1,150 a/r; 1.86/128 SSD, $1,350 a/r; 2.13/128 SSD, $1,694 a/r.
Best PowerBook G3 Deals, 11.24. Used 233 MHz WallStreet, $75; 266 MHz, $160; 400 MHz Lombard, $199; 400 MHz Pismo, $289; 500 MHz, $350.
Best 12" PowerBook G4 Deals, 11.23. Used 867 MHz SuperDrive, $348; 1 GHz Combo, $379; SD, $519; 1.33 GHz, $529; 1.5 GHz Combo, $549; SuperDrive, $609.
Best Mac Pro Deals, 11.23. Used 2.66 GHz 4-core, $1,300; 3.0 4-core. $1,919; refurb 2.66 4-core Nehalem, $2,149; 2.93, $2,549; 2.93 8-core, $4,999; new 2.26 8-core, $2,290.
Best Time Capsule and AirPort Deals, 11.23. Used 802.11g AirPort Extreme, $49; 500 GB Time Capsule, $150; new, $190; 1 TB dual-band, $280; 2 TB, $469; 802.11n AirPort Extreme, $170.
More deals in our archive.

About LEM | Support | Usage | Privacy | Contacts

Entire Low End Mac website copyright ©1997-2009 by Cobweb Publishing, Inc., unless otherwise noted. All rights reserved. Advice presented in good faith, but what works for one may not work for all. Please report errors to .
LINKS: We allow and encourage links to any public page as long as the linked page does not appear within a frame that prevents bookmarking it.
Access our RSS news feed at http://lowendmac.com/feed.xml.
Email may be published at our discretion; email addresses will not be published without permission, and we will encrypt them in hopes of avoiding spammers. If you prefer your message not be published, mark it "not for publication." Letters may be edited for length, context, and to match house style.
PRIVACY: We don't collect personal information unless you explicitly provide it. For more details, see our Terms of Use.
Low End Mac is an independent publication and has not been authorized, sponsored, or otherwise approved by Apple Inc. Apple, the Apple logo, Macintosh, iBook, iMac, eMac, iPod, iPhone, PowerBook, MacBook, MagSafe, Mac Pro, Apple TV, and AirPort are registered trademarks of Apple Inc. Additional company and product names may be trademarks or registered trademarks and are hereby acknowledged.