Hardware Autopsy
diately transmit a warning message to the
host controller. A read/write head that has
dropped a few nanometers out of spec, for
example, is likely fl ying too close to the plat-
ter. SMART recognizes this to be an impend-
ing head crash, where the read/write head
makes physical contact with the platter.
So how does your PC make you aware
of such problems? The most common
way is when you power up or restart your
machine. Your computer will perform a
power-on self test (POST), in which it will
quickly examine all the components con-
nected to the motherboard. When POST
checks your hard drive, it will display a
brief message that includes the drive’s
model number and its SMART status.
You can also check your drive’s
SMART status right from within Windows.
You’ll fi nd a number of shareware utilities
that can monitor a drive’s SMART status;
the freeware utility Speedfan is our personal
favorite. This super-useful program’s prima-
ry function is to control the speed at which
your PC’s various cooling fans spin—hence
its name—but it can also access SMART
readings for each of your hard drives. If
you’d like to check the health of your hard
drive, install and launch Speedfan. Click the
program’s SMART tab and look in the col-
umn titled “Attribute.” Attributes with no
icon next to them are just statistics; they
don’t have performance thresholds associ-
ated with them. Attributes with an OK in a
green circle are operating within their
established threshold. If you see a red circle
next to any of them (see image above), con-
sider yourself warned: Technology’s grim
reaper is sharpening his scythe.r & d BREAKING DOWN TECH —PRESENT AND FUTURE
72 MAXIMUMPC OCTOBER 2006 OCTOBER 2006 MAXIMUMPC 73
White Paper: SMART Hard Drives
NAND FLASH
These are the memory chips that store your data. This key uses 1GB of Samsung NAND
flash memory. There are various types of flash memory available but NAND is one of the
most popular and least expensive. In this type of memory, each cell holds one charged bit
representing either a one or and zero.USB Flash Drive
Admit it: You use your USB key every day but have no real idea what’s inside it
or how it works. Here’s the “inside” scoop.NAND FLASH
These are the memory chips that store your data. This key uses 1GB of Samsung NAND
flash memory. There are various types of flash memory available but NAND is one of theUSB Flash Drive
Admit it: You use your USB key every day but have no real idea what’s inside it
or how it works. Here’s the “inside” scoop.Monitoring a drive’s SMART messages
is just one of Speedfan’s many uses.
The red circle with the horizontal bar
is SMART’s way of saying that this drive
has exceeded its Spin Retry Count
threshold.ASIC
The memory key’s
ASIC (application-
specific integrated
circuit) is the
device’s brain.
This one is from
an M-Systems unit
and it consists of a
50MHz StrongARM
7 RISC processor. It
handles all the read/
write operations and
performs four-bit
error correction and
bad-block scanning
(to detect any flaws
or corruption in the
flash memory).PRINTED
CIRCUIT BOARD
A memory key’s integrated
circuits and other
components are soldered
onto the printed circuit
board. Manufacturers
often design the PCB to
accommodate more than
one flash memory chip,
so they can use the same
PCB to make more than
one model (a 512MB
key and a 1GB key, for
example)CRYSTAL
OSCILLATOR
This crystal
generates the clock
signal for the key’s
onboard processor.
All the components
onboard the
PCB synchronize
themselves to the
frequency this
crystal generates.
Overclocking this
oscillator would be
a bad idea.ENCLOSURE
This ultra-sophisticated,
plastic-alloy capsule
shields the key’s delicate
internal components
from the abuses of
spilled beverages, car
keys, and other items
you carry in your pocket,
and—most importantly–
–static electricity.LED
Every USB key has
a petite LED to
indicate read/write
activity; most,
including this one,
are blue.UndersideUndersideUnderside