IBM's high-priced PowerPC notebook makes AIX truly portable
Bruce Dawson
Although it's not the first RISC-based portable PC running Unix, IBM's RS/6000 N40 is the first using the new PowerPC chip, and it may be the fastest. Built by Tadpole, the N40 is a notebook version of IBM's RS/ 6000 running AIX, IBM's flavor of Unix. It is a lightweight, color notebook powered by a 50-MHz PowerPC 601 microprocessor with a 32-KB cache. Weighing just over 7 pounds with the battery installed, it has the near-laptop dimensions of 8.5 by 11.8 by 2 inches. The price of the basic system I reviewed, equipped with 16 MB of RAM and a 340-MB hard drive, is $11,995.
The internal battery lasts only 45 minutes to an hour; it's too bad the power-efficient 603 version of the PowerPC chip wasn't available at design time. IBM extends your
road time by shipping the N40 with two batteries, but you must shut down the system to switch them. Using the N40's save-and-resume feature, that process takes around 5 minutes--not bad for a Unix system, but still inconvenient. Another solution is an optional external battery pack that connects to the back of the N40 and extends battery life up to 4 hours.
Packs Power
This rugged little notebook packs a lot of power and features. The lightweight magnesium-alloy case makes it sturdy and doubles as a heat sink. The N40's built-in TFT (thin-film transistor), active-matrix color screen measures 9.4 inches diagonally and provides bright 640- by 480-pixel images and a wide viewing angle. The removable hard drive slides out easily to provide security or to enable different users to each have their own environment. A smaller (250 MB) drive is also available. You can expand the N40's memory from its base configuration of 16 MB up to either 32 MB or 64 MB by replacing the 8-MB modules in its two SIMM socket
s with higher-capacity units.
The N40 uses the same TrackPoint II pointing device found on IBM's ThinkPad portables. This mouse alternative proved to be quite a boon to portability, eliminating extra baggage and configuration time. However, unless I turned down its sensitivity, I found it to be more disconcerting than useful in vibration- or shock-prone environments, such as most forms of ground transportation. Old point-and-click habits die hard, and you're just as likely to select Close as Minimize in the X Window System if the vehicle you're riding in should hit a bump at just the wrong moment.
The N40 comes with a full set of external ports. The SCSI, parallel, serial, and audio ports use nonstandard connectors, but breakout cables are provided, so you can use standard cables to connect peripherals. The 15-pin AUI (attachment unit interface) connector requires an additional cable and transceiver for most Ethernet environments. A LocalTalk port provides another networking option. The N40's 8-
bit Fast SCSI-2 supports up to six external devices.
For desktop use, the N40 provides keyboard and mouse ports, as well as a 15-pin VGA connector with video-memory support (2 MB) for resolutions of up to 1280 by 1024 pixels with external monitors. For long-distance communications, there is both an internal 14.4-Kbps fax modem and an ISDN port. PCMCIA slots (two Type II or one Type III) will allow future Token Ring and wireless adapters. And for multimedia, the N40 comes with a built-in microphone and speakers, as well as a port for external audio.
The N40 supports a 256-color, 1280- by 1024-pixel virtual display on its 640- by 480-pixel LCD. Like some other Tadpole notebooks, the N40 supports panning by just running the cursor up to the edge of the screen, and you can zoom in and out with function-key combinations. In a Unix environment, it's a very nice feature to have. The LCD virtual-display feature also lets you simultaneously display on an external monitor with resolutions higher than 640
by 480 pixels.
The power supply is a svelte adaptive-voltage design that should work just about anywhere (110 to 240 V, 50 to 60 Hz) given an appropriate power cord. It's as light as they come. The adapter, power cord, charger, and two nickel-cadmium batteries all fit into the N40's canvas carrying bag (which lacks a shoulder strap).
Slimmed-Down AIX
AIX, which comes preinstalled, is so large and feature-rich that IBM had to pare some features to fit it onto the N40's 21/2-inch 340-MB removable hard drive. Fortunately, the only missing features are those you're unlikely to need on a portable system, such as most of the server software. IBM claims that the N40's reduced AIX remains fully compatible with AIX 3.2.5. IBM provides a CD-ROM with a full AIX distribution on it, so you can augment AIX's features once internal drives larger than 340 MB become available for the N40 (or if your N40 has a sufficiently large external hard drive and CD-ROM drive attached to it).
The only documentatio
n that came with the system was two thin spiral-bound notebooks describing how to attach cables to the N40, configure AIX, and use the NCE (Nomadic Computing Environment). All other documentation is on the distribution CD-ROM disk. Unfortunately, you have to install the information on your hard drive to read it, and there just isn't room. It's too bad the CD-ROM isn't structured so that you could use AIX's information browser to read the documentation data right off the CD-ROM. As it is, you can store the documentation on an external hard drive or on a network server.
Changing Environment
To those already familiar with AIX, the most interesting feature will be the NCE. It's a Tadpole-developed package of programs that provides a number of options for using the N40 in a changing environment. Most important for a Unix system, the save-and-resume feature lets you preserve the state of the system and restore it across power cycles relatively quickly. The feature requires an area of your hard drive the s
ame size as your memory capacity.
You can initiate a save by using key strokes, by pressing the power button, through a menu, or by closing the lid. You then push the power button to restore. This feature is useful for quickly picking up the N40 and going somewhere else. Saving the system state takes a minute or two of disk writing, so don't expect to close the lid and just vamoose; IBM cautions that the notebook should remain undisturbed while the drive is active. (I was able to place the N40 in its case and gently carry it off during its save cycle, but I wouldn't recommend this.) A similar sleep mode saves the system state to disk and then goes into a low-power condition. Recovery is instantaneous.
A Location panel in the NCE window lets you set up for several locations, each with its own name, time zone, phone numbers, and network configuration, to list some of the possible parameters. You select one of these names to switch your operating environment to the resources available at a particul
ar locale.
You can also select different peripherals through NCE so that you can use whatever resources are available at a site. You can pick up and go with the pause-and-resume feature and then quickly set up and work at a new site. AIX and NCE work together to resolve the problems traditional with changing hardware between boots. (However, servers at one site may not be available at another site.) Through NCE you can also make connections using Dial-in IP (SLIP), so you can use your central office's LAN resources via a modem.
Except for battery life, I found the N40 to be a nice notebook, if somewhat larger than I'm used to. It had sufficient horsepower to run the applications I could run, even if it didn't have all the applications I wanted to run. There are no WYSIWYG editors on the N40, for example--not even the freely available xedit or emacs. The Power Desktop GUI application that IBM provides is a nice facilitator for getting around in Unix's directory scheme, but it doesn't provide any
inherent value to the system.
For instance, there are no word processing, database, spreadsheet, business graphics, or other general-purpose applications. Most Unixes don't come with these applications, but I expected a little more for the premium price IBM demands for this notebook.
The N40's AIX comes with two versions of its capable SMIT system management environment, a character-cell version and a GUI version. The latter version takes up more than the entire VGA display. However, it has nice, large fonts, and you can get around in it easily enough using the pan-and-zoom features or if you have a high-resolution external display.
The N40 has many nice features that suit it as a portable PC. NCE's Location feature, for example, greatly enhances your ability to work effectively in multiple locations. Software consultants and support specialists should find that just this single feature makes the N40 worth serious consideration.
On the other hand, I found the N40 barely usable away
from A/C power, even with the two batteries supplied. As I mentioned, it's not that practical switching batteries because you must cycle power to make the switch. Additionally, I don't recommend trying to use the TrackPoint pointing device when under way in a bus or train. For some remote-site applications, however, the N40 could be indispensable. If you need AIX in a portable package, there's no substitute.
The Facts
IBM RS/6000 N40 $11,995
(as tested, with 16 MB of RAM and a 340-MB hard drive)
IBM Corp.
Old Orchard Rd.
Armonk, NY 10504
(800) 426-2255
international: (800) 426-1774
fax: (800) 426-4329
Unix Benchmarks
The Unix benchmarks were run in a single-user mode to give some idea of the system's raw performance, and in a multiuser mode to give an idea of how much overhead is involved in running AIX. In the single-user test, the benchmark had only the error logger server and the NCE daemon running. The multiuser test
added one remote NFS (NetWork File System) mount, the X display server, and the default number of servers--a fairly typical environment for a mobile user. The results are indexed. On the BYTE Unix benchmarks (version 3.11), a Sun SparcStation 1+ running SunSoft 4.3 = 1. Thus, the results below show the RS/6000 to be several times faster overall than the SparcStation 1+.
INDEX INDEX
TEST (SINGLE USER) (MULTIUSER)
Arithmetic (type = double) 4.8 4.8
Dhrystone 2 without
register variables 5.0 4.9
Execl throughput 5.1 5.0
Pipe-based context switching 2.1 2.3
Shell scripts (eight concurrent) 2.0 0.5
Due to lack of space on the 340-MB hard drive, both test sets failed to perform the file I/O tests.
Photograph: IBM's RS/6000 N40 packs most of the power of a f
ull Unix workstation into a notebook-size magnesium-alloy shell. As with any notebook, you give up storage capacity and screen size for portability.
Bruce Dawson is a consultant working for Virgin Software, Ltd. (Manchester, NH). He has been developing low-level Unix, VMS, and DOS applications for the last 10 years. He can be reached on the Internet at
jbd@virgin.mv.com
or on BIX c/o "editors."
PowerPC Hits the Road
