Computer Fundamentals
🔒 Log in to trackCore abbreviations and full forms
🔒 Log in to trackHigh-frequency full forms (learn as a table, SSC asks these directly):
| Short | Full form |
|---|---|
| CPU / ALU / CU | Central Processing Unit / Arithmetic Logic Unit / Control Unit |
| RAM / ROM | Random Access Memory / Read Only Memory |
| PROM / EPROM / EEPROM | Programmable / Erasable Programmable / Electrically Erasable Programmable ROM |
| VDU | Visual Display Unit (monitor) |
| USB | Universal Serial Bus |
| LCD / LED / OLED | Liquid Crystal Display / Light Emitting Diode / Organic LED |
| UPS | Uninterruptible Power Supply |
| BIOS | Basic Input Output System |
| POST | Power-On Self-Test |
| GUI / CLI | Graphical / Command Line Interface |
| OCR / OMR / MICR | Optical Character Recognition / Optical Mark Recognition / Magnetic Ink Character Recognition |
| DPI | Dots Per Inch (printer resolution) |
| AI | Artificial Intelligence |
| PCB | Printed Circuit Board |
| PDA | Personal Digital Assistant |
| CRT | Cathode Ray Tube (old bulky monitor) |
| HDD / SSD | Hard Disk Drive / Solid State Drive |
| CAD | Computer-Aided Design |
| IC / VLSI | Integrated Circuit / Very Large Scale Integration |
Abbreviations for internet/networking (HTTP, URL, ISP...) are collected in the internet-email and networking topics.
Detailed notes
Why this subtopic is pure marks
Every exam asks 1–3 direct full-form questions. There is no logic to apply — only a table to know. Learn them in families so one wrong expansion cannot slip past you.
CPU and system family
| Short | Full form |
|---|---|
| CPU / ALU / CU | Central Processing Unit / Arithmetic Logic Unit / Control Unit |
| BIOS | Basic Input Output System |
| POST | Power-On Self-Test (not 'Power On System Test') |
| UPS | Uninterruptible Power Supply (not 'Uninterrupted') |
| USB | Universal Serial Bus |
| GUI | Graphical User Interface |
Memory family
| Short | Full form |
|---|---|
| RAM / ROM | Random Access Memory / Read Only Memory |
| PROM / EPROM / EEPROM | (Erasable) (Electrically Erasable) Programmable Read Only Memory |
| SRAM / DRAM | Static / Dynamic RAM |
| Cache | Fast memory between CPU and RAM (not an abbreviation) |
Device and media family
| Short | Full form |
|---|---|
| VDU | Visual Display Unit (the monitor) |
| LCD / LED | Liquid Crystal Display / Light Emitting Diode |
| CRT | Cathode Ray Tube (the old heavy monitors) |
| HDD / SSD | Hard Disk Drive / Solid State Drive |
| CD / DVD | Compact Disc / Digital Versatile Disc |
| OCR / OMR / MICR | Optical Character Recognition / Optical Mark Recognition / Magnetic Ink Character Recognition |
| DPI / PPI | Dots Per Inch (printers) / Pixels Per Inch (screens) |
How wrong options are built
Exams do not ask tricky full forms — they ask plausible wrong ones:
- UPS → 'Uninterrupted' (correct: Uninterruptible).
- POST → 'Power On System Test' (correct: Power-On Self-Test).
- VDU → 'Video Display Unit' (correct: Visual Display Unit).
- PPI for printers (PPI is for screens; printers use DPI). Read every word of every option — one wrong adjective decides the answer.
Two memory hooks that settle half the family questions
- Reader trio: OCR reads Characters (a scanned page becomes editable text), OMR reads Marks (bubble answer sheets), MICR reads magnetic Ink (the code line at the bottom of bank cheques). C–M–I: Characters, Marks, Ink.
- ROM ladder: PROM can be programmed once; EPROM is erased with Ultraviolet light; EEPROM is erased electrically, right in the circuit. Each step makes erasing easier — that single idea answers every PROM/EPROM/EEPROM question.
A five-second checking habit
- Expand the letters yourself before looking at the options.
- Match word by word — first noun, then every adjective.
- If two options differ by one word (Uninterrupted/Uninterruptible), trust the table, not the ear.
Quick revision
- CPU/ALU/CU, BIOS, GUI, USB — know them cold.
- UPS = Uninterruptible; POST = Power-On Self-Test; VDU = Visual Display Unit.
- ROM ladder: PROM (program once) → EPROM (erase with UV light) → EEPROM (erase electrically).
- OCR = Characters, OMR = Marks, MICR = magnetic Ink on cheques.
- DPI = printers (dots); PPI = screens (pixels).
Types of questions asked
Every way this subtopic shows up in exams — how to recognise it, the formula or logic to use, and a solved example.
Type 1: Direct full-form recallvery common3 practice Q
'What is the full form of BIOS / ALU / GUI / USB?' — a plain expansion question with four expansions.
- Recall the family table the abbreviation belongs to (CPU family, memory family, device family).
- Expand letter by letter and compare word by word; do not recognise the option 'as a whole'.
- BIOS = Basic Input Output System; GUI = Graphical User Interface; USB = Universal Serial Bus.
Example: The full form of GUI is —
Graphical User Interface — the windows-icons-menus-pointer style of working, as against typing commands.
Type 2: Plausible-wrong expansion trapscommon4 practice Q
All four options look almost identical — the wrong ones change one adjective (Uninterrupted/Uninterruptible, Power On System Test/Power-On Self-Test, Video/Visual).
- Read every word of each option; the trap is one swapped word.
- Fixed traps: UPS = Uninterruptible Power Supply; POST = Power-On Self-Test; VDU = Visual Display Unit.
- If two options look nearly right, the longer-worded standard form is usually correct (Uninterruptible, Self-Test).
Example: The accepted full form of UPS is —
Uninterruptible Power Supply — a battery backup that switches in instantly when mains power fails. 'Uninterrupted' is the planted trap.
Type 3: Abbreviation ↔ device/domain matchingcommon4 practice Q
'DPI measures…', 'MICR is used in…', 'VDU refers to…' — the abbreviation is given with its use or device asked.
- Reader trio: OCR = characters (scanned text), OMR = marks (exam bubbles), MICR = magnetic ink (bank cheques).
- Resolution pair: DPI = dots per inch → printers; PPI = pixels per inch → screens.
- VDU = the monitor; BIOS = firmware chip that starts the machine.
Example: MICR technology is used mainly in —
Cheque processing in banks — MICR (Magnetic Ink Character Recognition) reads the characters printed at the bottom of a cheque in special magnetic ink.
Type 4: Odd one out / mismatched pair among abbreviationscommon2 practice Q
'Which is not a memory term?', 'which pair is wrongly matched?' — one option breaks the family.
- Test each option's full form against the family table.
- Memory family: RAM, ROM, PROM, EPROM, EEPROM, SRAM, DRAM, Cache. Anything else (RTOS, HTTP, GUI) breaks the family.
- For mismatched pairs, expand both halves and compare word by word.
Example: Which of the following is NOT related to memory?
RTOS — Real-Time Operating System, an OS type. RAM, ROM, PROM and DRAM are all memory terms.
Shortcut tricks
⚡ ROM family ladder
P -> EP -> EEPROM: each generation gets easier to erase - PROM (once, at manufacture/programming), EPROM (erase with UV light), EEPROM (erase electrically, in circuit). "UV for EPROM, Electricity for EEPROM."
Example: EPROM is erased using?
Ultraviolet light.
⚡ OCR-OMR-MICR trio
OCR reads Characters (printed text -> editable text), OMR reads Marks (exam bubbles), MICR reads Ink on cheques (banks). Characters, Marks, Ink = CRM.
Example: Bank cheque reading uses?
MICR (Magnetic Ink Character Recognition).
Where students lose marks
Expanding UPS as 'Uninterrupted' - the accepted form is Uninterruptible Power Supply.
Reading POST as 'Power On System Test' - it is Power-On Self-Test.
Confusing DPI (dots per inch, printers) with PPI (pixels per inch, screens).
Practice sets — 14 questions
Sets of 10, mixed across the question types above. Each answer comes with a step-by-step explanation.
Topic test · 10 questions
Suggested time 4 min · wrong answers go to your mistake notebook automatically.