chapter 8 Flashcards
The area on a tape or disk in which the head creates a flux reversal is called a ________ ________ or a __________ _____________
bit cell
transition cell
Which of the three types of servos that can be used in HDDs is most often used today?
Embedded servo
When ZBR is used, which of the tracks have the largest number of sectors?
Which of the tracks permit highest data transfer rates?
Outer tracks of the platter, Outer tracks of the platter
It is not necessary to allow a HDD that is brought in from the cold to adjust to room temperature before trying to use it?
False
What is the basic shape of a read/write head?
U-shaped
Magneto-resistive head assemblies actually contain two heads because a magneto-resistive head cannot write to a medium.
True
Name 3 applications of the 2.5” form factor
Laptop(notebook) HDDs
SSDs
hybrid drives
All of the above
A Femto slider has 3 distinct areas with complex shapes designed to float at a constant height above the surface of the disk at any location on the disk and to minimize height loss under high-altitude conditions (environment)
True
Third-party disk-partitioning tool such as Parted Magic can resize partitions without destroying data
True
Which of the items in the list below is Not a desirable result of making magnetic heads for HDDs smaller
Enabling faster seek times
Increasing the usable disk surface
Reducing platter wear when the disk starts and stops
What are the step(s) that are required to prepare a HDD for use.
Low-level formatting
Partitioning
High-level formatting
All of the above
Voice coil actuator that is characterized by being lightweight but creating azimuth error as it moves the heads across the surface of the platter?
Rotary actuator
__________ is the average time for a sector to be available after the heads reach a track
Latency
That timing signal is called a __________.
clock signal
What is the name of the circuitry that can be used in the read circuit to increase by 40% the amount of data stored on a disk
PRML (partial response maximum-likelyhood)
What is the name of the circuitry that can be used in the read circuit to increase by 40% the amount of data stored on a disk
PRML (partial response maximum-likelihood)
What is the name of the device that generates waveforms to optimize placement of flux patterns on the disk during writing and converts the waveforms back into binary data during reading?
Endec
Of the encoding techniques presented in the text, the _________ encoding technique provides the highest recording density.
rll
A body of material that supports the head is know as a _______________________
slider
Disk drive storage for computers was actually developed and introduced prior to tape drive storage for computers.
False
One Terabyte (T) is smaller than one Tebibyte (Ti)
True
When the flow of current through its coil is reversed it is called a _______________ reversal.
flux
An unrecoverable error is an error that cannot be corrected even after ECC has been applied.
True
Write an equation that relates average access time, latency, and average seek time.
Access time = Seek time + Latency
What type of waveforms does a head output when it is reading a tape or disk?
pulse (p 478)
Stepper motor mechanisms can move in increments of less than a single track and correct for temperature-induced errors
False
What is the name of the recording technique that aligns magnetic bits vertically rather than horizontally on the surface of a drive?
Perpendicular magnetic recording
If the platters of a HDD that are the thin-film
The platter looks like a mirror
If the platters of a HDD that are oxide-coated
The platter looks brownish-orange
____________ __________ = the number of bits/inch stored on a track multiplied by the number of tracks/inch
areal density
On an unmagnetized medium there are many magnetic particles (fields) each with its own direction of polarity. What is the overall resulting magnetism?
0
The name for all of the identically aligned tracks on both sides of all platters in a HDD is called a __________.
cylinder
PMR technology was first introduced commercially in floppy disks.
True
Name the advantages of using glass-ceramic material for the platter of a HDD rather than metal.
More rigid (can be made thinner), thermally stable
Current best practice is to run a head parking program before shutting the power off on a computer to avoid damaging either the heads or the platters.
False
What two factors determine media transfer rate of a HDD?
track linear density
Platter rotational speed
When does a contact start stop head touch the surface of a platter in a HDD?
When the drive is powered off
When does a contact start stop head not touch the surface of a platter in a HDD?
When the drive is powered on (during normal operation)
Servo in voice-coil actuators Indicate the position of the heads in relation to cylinders and positions the heads accurately over the cylinders
True
What action did the HDD industry take to increase storage efficiency and improve read error rates in HDDs?
Increased HDD sector size to 4 kB (advanced format) (p 512)
The time required for the heads to move from one cylinder to another cylinder a random distance away is called the Average __________ time
seek
