components Flashcards
types of digital devices
desktop computers laptop computers mobile phones tablet devices data storage - USB - Hard disk drives - Solid state drives - RAM sticks - Cloud storage
inside a computer
Motherboard Graphics card CPU RAM PSU HDD/SSD CD/DVD ROM drive
outside a computer
Screen Workstation/base unit Keyboard Mouse Printer External storage device
name 3 mobile operating systems
iOS
android
windows
SIM cards
Subscriber identification module
Come in 4 sizes: full size SIM, mini SIM, micro SIM, nano SIM
HHD - disk geometry
Hard drive disk
Made up of 1 or more platters coated with a magnetic material
geometry - disk geometry
a disks logical structure of platters, tracks and sectors
head - disk geometry
Device that reads and writes the data to a platter, there are 2 heads per platter, 1 reads the top side and the other the bottom side
track - disk geometry
Concentric circles on a platter where data is located
cylinders - disk geometry
a column of tracks on 2 or more platters
sectors - disk geometry
section on a track made up of 512 bytes
cylinder, head, sector maths
To work out the size of a hard drive from the CHS values: • C x H x S = tS • tS x BpS = total bytes • C = cylinders • H = heads • S = sectors • tS = total sectors • BpS = bytes per second
sectors
A sector contains 571 bytes however only 512 of those bytes are for data, the rest make up the header of the sector
The header contains information about the sector, such as its ID, the CHS information and some cylindric redundancy check digits to ensure the integrity of the data
solid state drives
Used in USB drives, laptops, tablets, and mobile phones and can cause digital forensic investigators issues when trying to recover data from them due to a feature called “wear-levelling”
wear-levelling
Wear-levelling moves the data on the drive from one memory cell to another, so all memory cells have equal use as each memory cell is only designed to perform between 10,000 to 100,000 reads/writes depending on their design
why is deleted data an issue
Deleted data is there for an issue because when something is deleted, the actual data is initially not deleted from the drive, just the references to it are removed, so with an SSD, the data will still be there but during the wear-levelling process other data could just be moved to the memory cells it was occupying.
garbage collector
When data is moved around during wear-levelling, the old address to the data is filed in an area of firmware in a file called “garbage collector” and the drive will automatically erase data in these areas by overwriting any data in these listed areas.
file systems
FAT – File Allocation Table
NTFS – New Technology File System
HFS/HFS+ - Hierarchical File System/plus
APFS – Apple File System
Ext – Extended File System
FAT and NTFS are what based file systems
windows
where are HFS and APFS found?
Macs
where would a Ext file system be found
linux machine
FAT file system
you would use a FAT based file system to use a USB drive to save data across multiple operating systems, but you can’t store files larger than 4GB in a FAT formatted drive.
NTFS drive
A Mac can read an NTFS based USB drive but under normal conditions it cannot write to an NTFS drive.
what are the two newest file structures
NTFS
APFS
