Individual Assignment: Disk Storage (Open Internet) Consider the hard drive on y
ID: 3706489 • Letter: I
Question
Individual Assignment: Disk Storage (Open Internet) Consider the hard drive on your favorite computer, which would normally be your laptop. Also, consider your most used auxiliary storage, which is likely to be a flash drive. Report on how files are stored on your hardware. Is FAT used, or another approach? What is the storage capacity? How is that capacity organized? (Partitions? Tracks? Sectors?) How many disk accesses does it take to read a 2048 byte file from your hard drive? How many disk accesses does it take to read a 2048 byte file from your flash drive? Show your work, and cite your sources.Explanation / Answer
Hard disk is a typical information stockpiling utilized as a part of PCs. Information is put away on the hard disk as 0 and 1. The piece of the hard disk that stores the information is known as platter. Platters are roundabout circle made of a non attractive material normally aluminum amalgam, glass or earthenware and are covered with a thin layer (10-20nm) of an attractive material. Platters are additionally isolated in to the tracks and divisions where tracks are concentric circles while areas are pie molded wedges on the track.Hard plate stores data as attractive fields. Information is put away carefully as little polarized districts on the platter where every locale speaks to a bit. To compose an information on the hard plate, an attractive field is put on the small field in one of these two polarities: N-S – If North Pole touches base before the south post and S-N – if the south shaft lands before the north shaft while the field is gotten to. An introduction in the one course (like N-S) can speak to the '1' while the contrary introduction (S-N) speaks to "0". This extremity is detected by coordinated controllers worked inside the hard disk.
The surface of the drive platter is organized
with coordinates, much like a map. Data is
stored in concentric tracks on the surfaces of
each platter. (A platter has two sides, and
thus, two data recording surfaces.) A typical
disk drive can have more than 2,000 tracks
per inch (TPI) on its recording surface. A
cylinder describes the group of all tracks
located at a given head position across all
platters. To allow for easier access to data,
each track is divided into individually
addressable sectors.
The process of organizing the disk surface
into tracks and sectors is called formatting,
and almost all hard disk drives today come
preformatted by the manufacturer. The
process of formatting a hard drive applies
addressing data to the platter's surface. In
almost all systems, including PCs and
Macintoshes, sectors typically contain 512
bytes of user data plus addressing information used by the drive electronics (although
some proprietary systems use other sector lengths). The disk drive controller, which
resides on the drive's PCB, uses the formatting information and addresses - much like a
tourist uses a city map - to guide data into and out of a specific location on the hard drive.
Without formatting instructions, neither the controller nor the operating system would
know where to store data or how to retrieve it.
In earlier hard drive designs, the number of sectors per track was fixed and, because the
outer tracks on a platter have a larger circumference than the inner tracks, space on the
outer tracks was wasted. The number of sectors that would fit on the innermost track
constrained the number of sectors per track for the entire platter. However, many of
today's advanced drives use a formatting technique called Multiple Zone Recording to
pack more data onto the surface of the disk. Multiple Zone Recording allows the number
of sectors per track to be adjusted so more sectors are stored on the larger, outer tracks.
By dividing the outer tracks into more sectors, data can be packed uniformly throughout
the surface of a platter, disk surface is used more efficiently, and higher capacities can be
achieved with fewer platters. The number of sectors per track on a typical 3.5-inch disk
ranges from 60 to 120 under a Multiple Zone Recording scheme. Not only is effective
storage capacity increased by as much as 25 percent with Multiple Zone Recording, but
the disk-to-buffer transfer rate also is boosted. With more bytes per track, data in the
outer zones is read at a faster rate. Quantum Corporation is a pioneer in Multiple Zone
Recording, and was the first manufacturer to implement Multiple Zone Recording on 2.5-
inch disk drive products.
Rotational speed = 10000 RPM. Thus, the time for one rotation is
1 minute 60 seconds 60 seconds
---------------- * -------------- = ------------- = 6ms per rotation
10000 rotations 1minute 10000 rotations
* = 6ms per rotation
There are three components to any disk access- seek time, rotational delay and finally transfer time.
Seek time = average seek time = 4.9ms
Rotational delay, because we are seeking on only one disk, is 1/2 * 6ms = 3 ms
One stripe unit is 8KB. Each sector is 512 bytes. Thus, one stripe unit is 16 sectors. Our disk has 200
sectors per track, and performs one rotation in 6ms. Thus, the transfer time is 16/200 * 6ms = .48ms
Thus, the total time = 4.9ms + 3ms + .48ms = 8.38ms
The write service time is the same