Exam Prep · CFA

CFA Final Revision

CACS 101 · 7 units · revision sheet, reference tables, predicted questions, and 1-day plan

Unit 1

Generations: 1G (vacuum tubes, 1940s), 2G (transistors, 1950s), 3G (ICs, 1960s), 4G (VLSI/microprocessors, 1970s+), 5G (AI/parallel)
Characteristics: Speed (MIPS/MFLOPS), Accuracy (no errors if correct input), Storage, Diligence, Versatility, No IQ
Classification by size: Supercomputer > Mainframe > Minicomputer > Microcomputer (PC, laptop, embedded)
Classification by purpose: General-purpose vs Special-purpose (ATM, gaming console)
Von Neumann architecture: CPU + Memory + I/O + Bus. Programs and data share same memory
Binary system: all data stored as 0s and 1s. 1 byte = 8 bits. KB=1024B, MB=1024KB, GB=1024MB
ASCII: 7-bit encoding for 128 characters. Unicode (UTF-8/16): supports all world languages
Types of computers: Analog (continuous), Digital (discrete), Hybrid (both)

Unit 2

CPU components: ALU (arithmetic/logic operations), CU (fetch-decode-execute), Registers (temporary fast storage)
Fetch-Decode-Execute cycle: PC→MAR→IR→decode→execute→store result. Repeated continuously
Memory hierarchy (fastest to slowest): Registers → Cache (L1/L2/L3) → RAM → SSD → HDD → Optical → Tape
RAM = volatile, loses data on power off. ROM = non-volatile (BIOS). Cache = fastest, most expensive, smallest
Primary memory: RAM, ROM, Cache. Secondary: HDD, SSD, USB, CD/DVD (persistent storage)
Input devices: keyboard, mouse, scanner, microphone, webcam, joystick, touchscreen
Output devices: monitor (CRT vs LCD vs LED), printer (inkjet/laser), speaker, projector
Bus types: Data bus (transfers data), Address bus (memory locations), Control bus (signals)

Unit 3

System software: OS, device drivers, utilities (antivirus, disk defrag). Manages hardware resources
Application software: word processors, browsers, databases, games — serve end users
OS functions: Process management, Memory management, File system, I/O management, Security
OS types: Batch, Time-sharing, Real-time (RTOS), Distributed, Network, Mobile
Programming language levels: Machine (binary) → Assembly (mnemonics) → High-level (C, Java, Python)
Compilation: Source code → Compiler → Object code → Linker → Executable (single pass)
Interpretation: Source code → Interpreter → Executed line by line (slower, portable)
Open source: source code freely available (Linux, Firefox). Proprietary: closed source (Windows, MS Office)

Unit 4

DBMS vs file system: DBMS eliminates data redundancy, inconsistency; supports multi-user, ACID transactions
ACID: Atomicity (all or nothing), Consistency (valid state), Isolation (concurrent transactions separate), Durability (persisted)
Data models: Hierarchical (tree), Network (graph), Relational (tables), Object-oriented
Relational model: data in tables (relations). Primary key = unique identifier. Foreign key = links tables
SQL basics: SELECT cols FROM table WHERE condition; INSERT INTO table VALUES; UPDATE table SET col=val; DELETE FROM table
Normalization: 1NF (no repeating groups), 2NF (no partial dependency), 3NF (no transitive dependency)
ER diagram: Entities (rectangles), Attributes (ovals), Relationships (diamonds), Cardinality (1:1, 1:N, M:N)
DBA role: design, install, maintain, backup/recovery, security, performance tuning of database

Unit 5

Network types: LAN (building), MAN (city), WAN (country/global). PAN (personal, Bluetooth)
Topologies: Bus (single cable), Star (central hub/switch), Ring (circular), Mesh (every device connected)
OSI 7 layers (bottom to top): Physical, Data Link, Network, Transport, Session, Presentation, Application
Mnemonic (bottom-up): Please Do Not Throw Sausage Pizza Away
TCP/IP model: 4 layers — Network Access, Internet (IP), Transport (TCP/UDP), Application (HTTP/FTP/SMTP)
IP addressing: IPv4 = 32-bit (e.g., 192.168.1.1). IPv6 = 128-bit. Subnet mask separates network/host
Protocols: HTTP(S)=web, FTP=file transfer, SMTP=send email, POP3/IMAP=receive email, DNS=name→IP, DHCP=auto IP
Internet services: WWW, email, FTP, VoIP, streaming, cloud. WWW ≠ Internet (WWW is a service on the internet)

Unit 6

Threats: Malware (virus, worm, trojan, ransomware, spyware), Phishing, Man-in-the-Middle, SQL injection, DDoS
Virus: attaches to files, spreads when executed. Worm: self-replicates over network, no host file needed
Trojan: disguised as legitimate software. Ransomware: encrypts files, demands payment
Symmetric encryption: same key to encrypt/decrypt (AES, DES) — fast, key distribution problem
Asymmetric encryption: public key encrypts, private key decrypts (RSA) — solves key distribution
Firewall: monitors and filters incoming/outgoing network traffic based on rules. Hardware or software
Password best practices: 12+ chars, mix upper/lower/numbers/symbols, no dictionary words, unique per site, use MFA
CIA triad: Confidentiality (only authorized access), Integrity (data not altered), Availability (system accessible)

Unit 7

Artificial Intelligence: machine simulation of human intelligence — ML, NLP, computer vision, expert systems
Machine Learning: algorithms that learn from data without explicit programming — supervised, unsupervised, reinforcement
Internet of Things (IoT): physical objects embedded with sensors/internet connectivity — smart home, wearables, industry
Cloud computing: on-demand computing resources over internet. Models: IaaS, PaaS, SaaS
Big Data 5Vs: Volume (huge), Velocity (fast), Variety (structured/unstructured), Veracity (accuracy), Value
Blockchain: distributed, immutable ledger. Each block has hash of previous — tamper-evident. Used in cryptocurrency
Virtual Reality (VR): fully immersive digital environment. Augmented Reality (AR): overlays digital on real world
E-commerce types: B2B, B2C, C2C, G2C. M-commerce = e-commerce on mobile devices