Part 1, Data on your computer Flashcards
what is
flash memory
this is technology that uses a chip which can maintain stored data without power. Some examples include SSDs, USB sticks
what are the three
main components of a HDD
the main components this has are
- platters
- head
- spindle
what is
formatting
this is the process of readying a disk with a file system so that it can be read and written to by any or a particular operating system
what is a
partition
on a hard drive
this is a way of dividing up a hard drives space each partition will be seen as a separate drive and can even hold different file systems
what three components are used to
structure data on a HDD
to achieve this the following compoents are used
1. tracks
2. sectors
3. clusters
describe what
tracks
are on a HDD
these are rings that follow the circumference of the HDD platter
how much
data can one track typically hold
this part of the HDD data structure can typically hold more than a megabyte of data
what are
sectors
on a HDD
these are arc shapes which divide the tracks into sections
how much data will a
sector
typically hold
within a HDD data structure this will typically hold
512 bytes
of data
describe what a
cluster
is within the HDD data structure
this is a series of adjacent sectors typically in powers of two
how much data will a
cluster
typically hold
typically this will hold 4 or 8 sectors.
since each sector typically holds 512 bytes. this will hold either
- (4 * 512) bytes = 2048 bytes
- (8 * 512) bytes = 4096 bytes
when using the
File Allocation Table 32 (FAT32)
or
New Technology File Sysem (NTFS)
file systems how is the data written to the hard drive
these two file systems make use of clusters.
when a new file is written it will be written to a new cluster.
it is the job of the operating system to allocate an appropriate number of clusters for the file.
if possible the data will be written contiguously otherwise it will be fragmented (only applies to HDDs)
how does a file system formatted to a disk
1. know where data is
2. know whether an area is free to use or not
a file system makes use of an
index table
to know these
give three points about
File allocation table 32 (Fat32)
some points on this file system are as folllows
1. this is the file system that was used by windows but is now usually used as a file system for flash memory
2. its index of every cluster is known as the file allocation table
3. was unable to write files larger than 4GB since it handled data in 32 bits
give two points about
New technology file system (NTFS)
some points on this file system are as follows
- this is the modern file system now used by windows
- its index table is known as master file table (MFT)
what is the name of the file system that
apple computers
use
this computers uses a file system known as
Apple file system
what is the name of the file system used by
linux
this operating system uses a file system known as
Extended file system 4 (ext4)
describe what
unallocated space
within a file system is
this is a discrete number of clusters that has no references in the index and is free to be written to. However, may hold past data
describe the
logical size
of a file
this is the size of the actual file in bytes
describe the
physical size
of a file
this size is found by the number of clusters that has been used to store the file
if a file has a logical size of 1280 bytes and the file system only uses 4 sectors per a cluster with each sector being 512 bytes then the physical size of the file must be 2048 bytes
describe what
slack space
is on a HDD
this is the difference between the physical size of the file and the logical size
It is best described as unused space due to the file being smaller than the cluster allocated to it
An important note here is that old data that was ‘deleted’ by the user could still remain in this space but unseen to the OS since there is no reference to it
what is
Latent data / ambient data
this is old data that remains in the slack space of a cluster
what are three best methods to
completely and safely remove data from a drive
some methods to accomplish this are
1. overwriting
2. degaussing
3. physical destruction
when removing data describe the process of
overwriting
this involves using the operating system or some other software to write ones and zeros to every part of the disk. Although this can be a time consuming process
when removing data from a HDD describe the process of
Degaussing
this is the process of exposing the hard drive to strong magnetic fields and in turn destroying the data that was held in a specific magnetisation
This is an expensive process because of the machines involved and if done incorrectly can leave data unchanged on the drive
when removing data from a HDD describe the processs of
physical destruction
this is the most secure way to remove your data from a drive it simply involves either burning crushing or shredding the drive and making it impossible to repair and hence read
