jeff@eng.umd.edu (Jeffrey Frey) (05/31/91)
BW performs a useful function but in the most simple-minded way. It does not monitor actual battery draw, but rather multiplies the draw of whatever subsystem is used by elapsed use time, determined from the builtin clock (builtin, that is, to the laptop) and subtracts what's been drawn from what a fully-charged battery is supposed to store. It's a purely passive program that does not sense such things as whether the backlight is on (you have to tell it whether it's on, and whether it's "low", "medium", or "high") or whether the charger is plugged in. There is no information as to whether it senses when the disk drives are running. The "generic " version is really a fill-in-the blanks thing: the user has to experimentally determine how long his battery lasts under his own average use. He puts this in the program which then counts down . Very simple. The advantage of the program is that it does have built-in values of battery draw for various components, and maximum battery life, for the computers for which it is appropriate (these values are supplied by the manufacturers; apparently Toshiba and Zenith were the most cooperative). The disadvantage is that it costs about $30 for a pretty simple piece of software. BW does record the charge it thinks is remaining in the battery when you shut the machine down, so the total battery depletion is cumulative from use to use., and between charges. BUT--some computers use battery charge even while off, e.g., the MiniSport while its RAMdisk is in maintaining mode. Whether BW accounts for this or not, I have not yet determined.... Jeff