-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 2000-06-15-01:07:44 Jerry Scharf:
One thing I know to watch for is periodic battery replacement. It turns out that running a laptop with a battery in it with AC on all the time will slowly erode the life of the battery.
That was definitely a major and severe problem at least a few years back; when the state of the art laptop used an NiCd battery, and had fairly dumb charging circuitry that easily overcharged --- and so overheated, and hence damaged --- the batteries, leaving it plugged in all the time killed it relatively quickly. People confused this with the subtle "memory effect", which they'd never be able to notice in laptop use. But a modern laptop, with brilliant power management software managing the health of a LiIon battery doesn't seem to suffer from this problem nearly as badly. I've been using my Sony Vaio 505TX for a year as my desktop computer; it's run pretty much a superset of 9-5 M-F plugged in to wall power, and I still get a reasonable battery run. And I'd still expect to use an external UPS with the laptop servers; I'd just expect the laptop's battery to provide a little extra coverage, and ability to ride over the switching. Plus it wouldn't load the external UPS --- or the air conditioning --- as hard. I honestly think that laptop designers and manufacturers have figured out people use their products as very compact desktop computers. In fact, if I'm recalling correctly, Toshiba pulled out an early commanding lead in the laptop industry in significant part because they had a _huge_ local market of office users whose office desks didn't have room for a US-styled "desktop" system.
The other is that the I/O on laptops sucks compared to PCI. For things that aren't major traffic handlers (like your DNS and DHCP examples) this is not a hit. Do any of the O/Ss out there get full rate out of a 100bT PC card?
As you say, for some jobs it's not an issue. For sure it's easy to get 10Mbps; I've done that for some time now with Linux through a 3C589. I haven't tried my 3C575 recently; a couple of Linuxes ago it solidly hung the system. But CardBus _claims_ to support data rates up to 132MB/sec. Even if it's hard to tweak a CardBus 100BaseT to run at full speed (I do not know), I honestly don't see that as being a major limitation for the kinds of applications to which a laptop would be otherwise suited. Maye it just reflects my youth and inexperience, but I tend to start thinking about higher-speed interfaces (faster than 10BaseT) about the same time I'm worrying about tuning a striped or raided disk farm with multiple controllers. A laptop with a single low-power (and hence low-rpm) IDE drive isn't competing at the high-performance end of things. There's actually a funny story there. I started using a laptop as a desktop computer before CardBus came around, and so got accustomed to the PCMCIA slot imposing a 4Mbps throttle on my ethernet. I couldn't figure out why people bothered with 100BaseT cards at all. I'd even confirmed the 4Mbps bottleneck with pathchar. Then I started with a new laptop setup, and was seeing real observed bandwidths up close to 10Mbps out of the likes of ftp, and was puzzled for a while. - -Bennett -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.0 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE5SN5tL6KAps40sTYRAhjmAJ9EARos8O3ZGLLCMgcypgrJ9tqooACgjpjS L/qsSAY05nY41iTNHGOfQPY= =IV/B -----END PGP SIGNATURE-----