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A few months ago I got a ThinkPad T42p to replace my aging X21. I was a bit reluctant to get a T series box again, because several years ago I got a T21 and was extremely unhappy with it. In fact, after about 3 months, I sold it and replaced it with an X series for nearly half the price. However, I was really wishing for a larger display than the X series 12". I use my laptop as my primary machine, so a bigger screen was a huge win.


The IBM ThinkPad T42p (2373-HTU) is a 1.8GHz Pentium M which comes stock with 1GB of RAM, Intel Pro Wireless 2100 802.11b wireless, and 1600x1200, 15" display. The video is an ATI FireGL Mobility T2. It comes with the extended-life battery, and a 3 year “depot” warranty. The T series is the roughly 5 pound laptop with 15" display, 2 PCMCIA card slots, and a removable device bay which comes with a DVD+RAM drive, second battery, or the like.

I had previously had a ThinkPad T21 and was extremely unhappy with it. The two largest problems were the video, an S3 Savage chip-set, and the battery life (around 2 hours with the system battery and 3 hours with the extra $120 “UltraBay” battery in place of the DVD drive). The S3 video was crashing regularly, even when running the latest S3 drivers, about once a day, unless I disabled all acceleration. With all acceleration turned off, even simple text was fairly slow rendering (like scrolling a text window).

The T42p, I'm pleased to report, I'm extremely happy with. The ATI video just works, though my 3D performance is pretty bad using the stock xorg driver. The system battery gets a solid 3 hours of life under my normal use. The major complaints I had for the T21 have been adequately addressed.


I simply pulled the hard drive from my old laptop, which was running Fedora Core 3 with KRUD extensions, and put it in this box. On the first boot I ran the system-config-display program to re-configure it for the new chip-set. Absolutely no problems. I have no problems when doing either software or S3 ACPI suspend with the video, and don't have to do any tricks with switching to the text console before suspend.

I almost never do any 3D graphics. In glxgears, I get around 260 frames per second with the stock xorg driver. I know Kevin, on his old laptop, is getting more than 1000 frames per second, but I haven't done anything about switching to the ATI driver or tuning performance. Text and browser performance is just fine.

Kevin came across this score. Under the “Section "Device”“ section for "Videocard0”, add the line:

Option      "DynamicClocks" "true"

This enables dynamic clocking on the video card, and can result in lower battery consumption if you aren't hitting the video hard. I haven't done much in the way of testing, but last night I Hacking Society I went the full 3 hours without needing battery and starting with less than a 90% charge. Before I've been able to just make it the 3 hours from a full charge.

DVD or UltraBay Ejection

The newer 2.6 kernels include kernel support for ejecting the DVD drive and doing other IBM-specific things. For example, if you do “echo eject >/proc/acpi/ibm/bay”, it will shut down the bay and allow you to swap the device that's in there. You can also enable/disable the Bluetooth and “ThinkLight” keyboard light, and switch video output modes, plus get the status and probably control the dock. I don't use the dock, so I don't really know what the status is there. I've done an eject of the DVD drive, and it seemed to work fine.


The T42p includes both a touchpad and the eraser-like TrackPoint pointing devices. I'm really glad about this, because I've always liked the eraser, and wasn't sure I'd like the pad. After about a month, I found I was never using the pad, and mostly it was just getting in the way. It would often detect my thumb when it was several millimeters from the surface, and so clicking on a button above it would make my pointer go off in some random location. I ended up disabling the pad in the BIOS and have been happy ever since.

The TrackPoint includes 3 mouse buttons. Kevin found a patch to enable the advanced features of the TrackPoint, such as click to scroll, press to select, and others. I haven't tried it yet, I'm not super interested in those functions.


It comes with built-in 802.11b in the form of the Intel Pro Wireless 2100. This driver recently seems to have gotten reasonably stable, though it doesn't support HostAP mode. Even 6 months ago, it was in pretty bad shape, but so far I've had few problems with it. You do have to obtain and build the driver on your own, in most cases.

You will have to remove the driver before doing an ACPI S3 suspend, or your wireless will stop working until you reboot.

I also purchased the Atheros 802.11 a/b/g card with the unit, and ran it for a month or two. The MadWiFi driver for this card worked, but had several annoyances for me. First of all, it scans all the frequencies, and was taking several minutes to associate with an AP. Also, none of the versions of the driver I tried supported scanning, which is a big annoyance when you don't know exactly what AP you want to associate with (at a new coffee shop, or when traveling, for example). Also, it claims to support locking down to just 802.11b/g mode, but that never worked for me. It defaults to 802.11a, so when I tried HostAP mode, it would stick in 802.11a mode and I couldn't get it to change to 802.11b. Nobody else has the 802.11a card, so I was able to act as an AP for… Nobody.

I ended up switching back to the IPW2100 card and have been happy with it, though it does seem to have sporadic problems with losing signal at some coffee shops that the Atheros didn't seem to.


Absolutely no problem. Even over a suspend.


For the first 2 months, I was strictly using software suspend (swsusp2) from a kernel that Kevin provided me. It worked well, extremely well. However, with 1GB of RAM it can take quite a while to suspend and resume. Up to a minute each. On the other hand, you can boot another OS, boot a Knoppix or other Live CD (as long as it doesn't touch your normal partition) or swap batteries while software suspended.

I've recently switched to using the ACPI S3 suspend, since Ed Hill recently said that it's working fine on his T42p and pointed me at the appropriate modifications to the kernel boot line. You simply have to add “pci=noacpi acpi_sleep=s3_bios” to the “kernel” line in the “/etc/grub.conf”, and then you can use the ACPI “Suspend to RAM”. This takes around 5 seconds to do, instead of the 30 to 50 that Software Suspend takes.

Ed reported that he was sometimes seeing his time be wrong after a suspend, so I run the following commands to suspend:

/sbin/hwclock --systohc
   echo 3 >/proc/acpi/sleep
   /sbin/hwclock --hctosys

That works around the time issues by saving and loading time to the hardware clock. Note that I also have to shut down my wireless device and “rmmod ipw2100”, then reload and restart after the suspend.

Also, apparently some laptops use excessive power when you S3 suspend them. Kevin pointed out a script that clocks battery loss while suspended, and determines if your laptop experiences this. The problem is apparently that a full charge will only last about 8 hours, instead of 6 days. The T42p seems to not have that problem, according to the stats it will last 6 days on a full charge while suspended. Not that I could last 6 days without using my laptop.

Access IBM Button and Others

The “tpb” package includes a daemon that can run a program when the blue “Access IBM” button is pressed, and display status when other special buttons are pressed such as the volume buttons, and LCD brightness. The volume/brightness feedback on the display is nice, but the thing I use it mostly for is to bind the blue Access IBM button to doing a suspend. It simply calls “sudo /path/to/dosuspend”, and is very handy. I've toyed with the idea of having the power button do that, but haven't set that up yet.

Security Chip

The T42p has the Embedded Security Subsystem chip in it, which can act as a vault for your private keys and the like. I haven't tried it at all.

DVD Drive

Seems to work fine. I've burned CDs and CD-RWs on it with no problems. I think I've read a DVD+RW on it, but I haven't tried burning a DVD+RAM. It's a little slow, but that's not unusual for a laptop optical drive. To be honest, I almost never use the optical drive. In fact, I'd be tempted to replace it with a second battery if the main battery weren't so mighty.

Battery Life

This box comes with the “Extended” battery, which protrudes from the back of the system a little. The life on the X21 I had was about 2.5 hours, so the extended T42p cell at a solid 3 hours is something I'm pretty happy with. Of course, the new X41 boxes have extended batteries that can push it up to 7 to 10 hours. That would be pretty amazing. However, the solid 3 on this setup is just fine.

You can also load a second battery in the UltraBay in place of the DVD and get something on the order of 4 to 4.5 hours. That would be pretty good, but I really don't feel the need for it these days.


My previous box was a Celeron 1.2GHz, and this is a 1.8GHz Pentium M. I was awfully tempted by the 2.2GHz step up model, because compiles on the 1.2GHz box could sometimes take a while. I realize the GHz numbers don't always compare linearly, but I was quite pleasantly surprised when I found that the 1.8GHz P-M is fairly comparable in performance to the 2.8GHz servers we're deploying and considering “speedy”. I don't know how they do it, but it's a speedy box.

Carry Case

While not technically part of the laptop as delivered, I would like to make special mention of this Eagle Creek bag I got for the laptop. My previous bag just wouldn't hold the new laptop, it's too big. I spent a long time at a local store that has a huge selection of bags, and actually loaded my stuff into a bunch of different bags to try out. One of the complaints I had about the previous bag was that it was an “over one shoulder” bag, and really didn't have any other ways to carry it, not even a handle.

The Eagle Creek I got is smallish, but not so small that I can't carry what I need. A zipper can expand it so it can carry even more stuff. It carries plenty though. The laptop just fits exactly in the slot provided for it, though the Velcro flap won't fasten over the extended battery. Not a big deal, because I'd probably never use it anyway.

One thing that sold me on it is the range of carry options. It includes a shoulder strap, which is how I usually carry it, but it also includes handles and back-pack straps. On the recent trip to D.C., my shoulder was unhappy from all the carrying of it I had been doing (the stock shoulder strap is not great, I'm thinking of upgrading it to Eagle Creek's after-market strap). Then I remembered that it could convert to a backpack, which worked extremely well. It made it no problem to carry on the 1.5 mile walk to and from the convention location.

It looks like Eagle Creek calls it the “Convertabrief”. Not the cheapest bag at $100, but it turned out to be the cheapest of the 3 final contenders when I went through the smoke test at the store. Looks like you can get them for $85 on line, but it was definitely worth the extra $15 to get the chance to do a hands-on of the different bags.

In Conclusion

It works great. I'm totally happy with it. Absolutely nothing wrong with it. I got the upgraded warranty, 3 years next day on-site plus this extra protection which apparently covers accidental damage. Considering how beat up my last laptop was after 2 years (I carry it with me everywhere). In fact, I'm thinking of upgrading it to 4 years, because I'm so happy with the box.

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