Lower voltage results in lower power consumption which results in less heat.
Lower clock speed also results in
Lower voltage enables smaller rise time which enables higher clock speed. By instead using lower clock speed, the result is that lower voltage enables lower heat generation for this second reason, in addition to enabling lower heat generation by lowering power consumption.
Laptop: to check the
battery: just charge it for 15 minutes with computer powered off. Then unplug the power cord to run the computer without AC — see if it runs. If it runs,
the batteries hold at least some charge.
The battery meter
(in the taskbar tray or under Control Panel > Power Options) is meaningful, and should be consulted, when the ac power is unplugged.
Do laptop battery calibration,
to see how well the battery is working: You may need to first set all power management settings to "never shutdown," then fully charge the battery. Start computer
in Safe mode, disable screensaver and with all all power management settings
still set to “never,” unplug AC, and fully discharge the battery, timing how long this
takes. Fully discharge means allow it to run
all the way down until the computer shuts off automatically (at about 10% of charge). How long it takes to fully discharge gives you an idea of how good the battery is. Once the laptop battery has fully discharged,
charge it back up again and restore the screensaver and power management
Laptops generally accept PCMCIA cards
There are 3 PCMCIA card types.
1, 2, and 3.
They are all 54 mm wide and 85.6 mm deep (they go into the case a long way). They vary in thickness according to the type.
PC card is new name
for pcmcia. Card that is hot swappable relies on socket services
to be hot swappable. Typical uses:
Memory (SRAM, Flash, etc).
I/O (modem, network card, etc)
Mass storage device.
G0 normal, G1
sleep, G2 soft off. Sleep modes (S), cpu states (C)
Global states: G0
is normal, full power, “hard on” - that’s my term. G1 is power-saving
G1 has 4 submodes
called Sleep modes, S1 – S3. Refer to various combos of cpu and memory
states, once hd is powered down. Cpu states (C) refer to cpu alone.
C0 (normal) to C3.
Higher number more
S1. CPU is
still on but not executing. Memory is still powered. Disks and other
devices are powered down.
S2. Not typically
used, cpu is powered down.
standby mode, generic term is suspend to RAM: only the RAM
S4 is hibernation
in Windows, generic term is suspend to disk. hibefil.sys
soft off. (normal off)
G3 is mechanical
off, hard off. Only clock and bios setup parameter chip (cmos chip)
is running, on battery. Power cord can be removed.
C0 is normal.
C3 is sleep cache flushed.. Between the 2 are lesser degrees of cpu
off. C1halt, wakes up fast.. C2 stop-clock, no clock
cycles, takes longer to wake.
In short, standby
is G1, S3; hibernation is G1, S4.
The Fn key is a special shift key that allows
you to select alternative functions on F keys, as well as on some of the
regular character keys. It internal functioning is slightly different than
that of the other shift keys, in that the key combination sends out a completely
different key code when the Fn key is depressed. The Fn key alone generally does not
generate its own scan code. It is usually near the Ctrl key.
Typically Fn plus F1 or F2 allow
you to control screen brighness. Fn-PgUp and Fn-PgDn — sound volume. Fn-Bksp
toggles sound mute. Fn-F8 is often NumLock. Fn-F5 toggles display between
builtin, external, and both. Fn-F12 – hibernate.