Information Systems Audit · One-liners

1 What is COMPUTER?

is often expanded as "Commonly Operated Machine used in Technical and Educational Research".

2 What is CPU?

is the single most-tested item from this chapter.

3 Arithmetic Logic Unit (ALU)?

the part that actually does arithmetic (+, −, ×, ÷) and logic (AND, OR, NOT, XOR, comparisons). It receives operands from registers, performs the operation in hardware and writes the result back to a register.

4 Control Unit (CU)?

the traffic policeman of the CPU. It fetches instructions from memory, decodes them, generates the timing & control signals, and tells the ALU/registers/memory/I-O exactly what to do, in what sequence.

5 Memory / Register Unit?

a small set of ultra-fast on-CPU storage cells (registers) that hold the operands the ALU is currently working with, the address of the next instruction (the Program Counter, PC), the current instruction (the Instruction Register, IR), the status flags etc.

6 Store — held numbers, fed data & intermediate results?

Memory / RAM

7 Mill (Arithmetic Unit) — performed arithmetic operations?

ALU

8 Control — checked sequence of operations?

Control Unit

9 Input — to enter numbers and instructions?

Input devices

10 Output — to display results?

Output devices

11 1st — Period / Switching technology / Speed (add) / Memory / Languages / Example?

Period: 1940–1956; Switching technology: Vacuum tubes; Speed (add): 200 ms; Memory: Very small (KB); Languages: Machine, Assembly; Example: ENIAC, UNIVAC, EDVAC, EDSAC, IBM 701

12 2nd — Period / Switching technology / Speed (add) / Memory / Languages / Example?

Period: 1956–1963; Switching technology: Transistors + magnetic core; Speed (add): 10 ms; Memory: Few KB to MB; Languages: FORTRAN, COBOL, ALGOL; Example: IBM 1401, IBM 7090, CDC 1604

13 3rd — Period / Switching technology / Speed (add) / Memory / Languages / Example?

Period: 1964–1971; Switching technology: Integrated Circuits (IC, SSI/MSI); Speed (add): 1 µs; Memory: MB; Languages: C, BASIC, PL/1; Example: IBM 360, IBM 370, DEC PDP-8 (mini)

14 4th — Period / Switching technology / Speed (add) / Memory / Languages / Example?

Period: 1971–Present; Switching technology: Microprocessor (LSI / VLSI) — up to ~50,000 transistors/chip in early VLSI; Speed (add): ns; Memory: MB to GB; Languages: C++, Java, Python; Example: IBM PC, Apple Macintosh, modern x86/ARM PCs

15 5th — Period / Switching technology / Speed (add) / Memory / Languages / Example?

Period: Present future; Switching technology: ULSI + AI / NLP / Parallel & Quantum architectures; Speed (add): sub-ns / parallel; Memory: TB to PB; Languages: Natural-language, Prolog, LISP, ML frameworks; Example: IBM Watson, Deep Blue, GPT-class systems, quantum prototypes

16 Analogue computers?

measure continuous physical magnitudes (voltage, temperature, pressure, flow). They do not compute with discrete numbers. Example: a petrol-pump computer that converts the continuous flow of petrol into a price; speedometer; thermometer-based industrial controller. Mostly used in scientific &…

17 Digital computers?

operate on discrete numbers / characters expressed as digits in binary (0/1). Almost every modern computer (including all banking computers) is digital.

18 Special-purpose digital computer?

dedicated to one task; instructions are permanently built in (firmware). Examples: ATM controller, washing-machine MCU, missile guidance computer.

19 General-purpose digital computer?

runs any program loaded into memory. Examples: PC, laptop, server, smartphone.

20 Hybrid computers?

combine analogue + digital. Used in medical equipment (ICU monitors), petrol-pumps, weather stations, aircraft control systems. Continuous input (sensor) A/D converter digital processing D/A converter continuous output.

21 Supercomputer — Size & cost / Users at a time / Speed / Typical use in banking?

Size & cost: Room-sized; ₹ tens-of-crores; Users at a time: 1 problem at a time, massive parallelism; Speed: petaFLOPS / exaFLOPS; Typical use in banking: Risk simulations, weather/forex modelling, AI training (e.g., PARAM, Cray, Fugaku)

22 Mainframe — Size & cost / Users at a time / Speed / Typical use in banking?

Size & cost: Room-sized; ₹ crores; Users at a time: Thousands concurrently; Speed: very high; Typical use in banking: Core Banking Solution servers in large PSBs (IBM Z, Unisys); CBS database, GL, posting engine

23 Minicomputer (Midrange / server) — Size & cost / Users at a time / Speed / Typical use in banking?

Size & cost: Refrigerator-sized; Users at a time: Hundreds; Speed: high; Typical use in banking: Departmental servers, branch servers (AS/400, IBM Power, Sun SPARC)

24 Microcomputer (PC / Workstation / Laptop) — Size & cost / Users at a time / Speed / Typical use in banking?

Size & cost: Desktop; Users at a time: 1 user; Speed: moderate; Typical use in banking: Branch teller PC, RM laptop, ATM controller

25 Hardware?

the physical, tangible components: CPU, motherboard, RAM stick, HDD, SSD, monitor, keyboard, cabinet, NIC card, router. "What you can kick."

26 Software?

the set of instructions, data or programs that operates the hardware and performs specific tasks. "What makes the hardware kick." Categorised into

27 System software?

OS (Windows, Linux, Unix, macOS, AIX, z/OS), device drivers, firmware, utilities.

28 Application software?

banking application, MS-Office, browsers, mobile-banking app.

29 Middleware?

sits between OS and application — message queues, application servers, ESBs.

30 Register?

fastest, smallest (bytes), sits inside the CPU itself. Holds operands of the current instruction.

31 Cache?

small (KB to a few MB), very fast SRAM between CPU and RAM. L1 sits on each core; L2 is per-core or shared; L3 is shared. Reduces the average memory-access time.

32 RAM (Random Access Memory)?

the main working memory. Volatile — contents lost on power-off. Two types: DRAM (slower, denser, cheaper — used for main memory) and SRAM (faster, used as cache).

33 ROM (Read-Only Memory)?

non-volatile; holds firmware / BIOS / boot code. Variants: PROM, EPROM, EEPROM, Flash.

34 HDD (Hard Disk Drive)?

magnetic platters with read/write heads; cheap per GB; ms latency; mechanical, hence fragile.

35 SSD (Solid State Drive)?

NAND-flash based; no moving parts; µs latency; 5–20× faster than HDD; higher cost per GB but dropping fast. Banks have largely moved CBS production storage to enterprise SSD/NVMe arrays post the 2023 IT Master Direction's hardware refresh expectations.

36 Tape, optical (DVD, Blu-ray), magneto-optical?

used for archival and backup. Tape is the staple of bank DR/BCP backups because of low cost per TB and long shelf life.

37 1 nibble?

4 bits

38 1 byte?

8 bits

39 1 KB?

1,024 bytes (2¹⁰)

40 1 MB?

1,024 KB (2²⁰)

41 1 GB?

1,024 MB (2³⁰)

42 1 TB?

1,024 GB (2⁴⁰)

43 1 PB?

1,024 TB (2⁵⁰)

44 1 EB?

1,024 PB (2⁶⁰)

45 Keyboard?

alphanumeric & function keys.

46 Pointing devices?

mouse, trackpad, trackball, joystick, touchscreen, stylus, light pen.

47 Scanners & readers?

MICR (Magnetic Ink Character Recognition) reader is examiner-favourite — used in cheque clearing (CTS) to read the 9-digit code line. OCR (Optical Character Recognition), OMR (Optical Mark Recognition — for examination answer-sheets), bar-code reader, QR-code scanner, biometric scanner…

48 Voice / audio?

microphone, voice-recognition system.

49 Imaging?

digital camera, web-cam.

50 Monitor / display?

CRT (legacy) LCD LED OLED AMOLED. Banking ATMs use LCD/LED.

51 Printers?

Impact (dot-matrix, daisy-wheel, line-printer — DMP still used for passbook & cheque printing) vs Non-impact (laser, ink-jet, thermal — receipts/POS).

52 Plotters?

for large engineering drawings.

53 Audio?

speakers, headphones.

54 Special output?

passbook printer, pin-mailer printer, receipt printer in ATM/POS.

55 Binary — Base / Digits / Use?

Base: 2; Digits: 0, 1; Use: Native to all digital electronics

56 Octal — Base / Digits / Use?

Base: 8; Digits: 0–7; Use: Compact representation of 3 bits at a time (used in older UNIX file permissions)

57 Decimal — Base / Digits / Use?

Base: 10; Digits: 0–9; Use: Human

58 Hexadecimal — Base / Digits / Use?

Base: 16; Digits: 0–9, A–F; Use: Compact representation of 4 bits at a time (memory addresses, colour codes, MAC addresses)

59 0 — B / Sum / Carry?

B: 0; Sum: 0; Carry: 0

60 0 — B / Sum / Carry?

B: 1; Sum: 1; Carry: 0

61 1 — B / Sum / Carry?

B: 0; Sum: 1; Carry: 0

62 1 — B / Sum / Carry?

B: 1; Sum: 0; Carry: 1

63 ASCII (American Standard Code for Information Interchange)?

7-bit code (128 characters) extended to 8-bit (256 characters) for non-English. Examples: 'A' = 65 = 0100 0001; '0' = 48 = 0011 0000; 'a' = 97. ASCII is the default in almost all modern files.

64 EBCDIC (Extended Binary Coded Decimal Interchange Code)?

8-bit IBM mainframe encoding. Still used in legacy mainframe banking systems (IBM Z, AS/400).

65 Unicode?

universal encoding for every script in the world. Variable-width encodings: UTF-8 (1–4 bytes — backward-compatible with ASCII; dominant on the Web), UTF-16, UTF-32. Unicode covers Devanagari, Tamil, Bengali, Gurmukhi, Arabic, emojis etc. and is therefore the foundation of all Indian-language…

66 BCD (Binary Coded Decimal)?

each decimal digit stored in 4 bits. Used in financial calculators for exact decimal arithmetic (no binary-floating-point rounding error).

67 0 — B / A AND B (· or ∧) / A OR B (+ or ∨) / NOT A (Ā or ¬A)?

B: 0; A AND B (· or ∧): 0; A OR B (+ or ∨): 0; NOT A (Ā or ¬A): 1

68 0 — B / A AND B (· or ∧) / A OR B (+ or ∨) / NOT A (Ā or ¬A)?

B: 1; A AND B (· or ∧): 0; A OR B (+ or ∨): 1; NOT A (Ā or ¬A): 1

69 1 — B / A AND B (· or ∧) / A OR B (+ or ∨) / NOT A (Ā or ¬A)?

B: 0; A AND B (· or ∧): 0; A OR B (+ or ∨): 1; NOT A (Ā or ¬A): 0

70 1 — B / A AND B (· or ∧) / A OR B (+ or ∨) / NOT A (Ā or ¬A)?

B: 1; A AND B (· or ∧): 1; A OR B (+ or ∨): 1; NOT A (Ā or ¬A): 0

71 XOR (Exclusive OR)?

output is 1 only when inputs differ (1 ⊕ 0 = 1, 1 ⊕ 1 = 0). Used in half-adders and in cryptography (one-time pad).

72 XNOR?

opposite of XOR; equality check.

73 Data?

raw, unprocessed facts (e.g., a list of cheque numbers and amounts).

74 Information?

data that has been processed into a useful form (e.g., today's clearing total per branch).

75 Knowledge?

information combined with experience and context (e.g., "branch X's clearing volume on Mondays is typically 1.7× the daily average — staff accordingly").

76 Batch processing?

a number of similar transactions are grouped and processed together at scheduled times. Highly efficient when the volume is huge. End-of-Day (EOD) and Beginning-of-Day (BOD) batches in CBS — interest application, charges, GL roll-over, statement generation — are classic batch jobs.

77 On-line / On-line Transaction Processing (OLTP)?

system processes each transaction as it is entered, with the data fed directly to secondary storage under CPU control. Every entry carries a transaction code; validation happens before storage; master record updated immediately. Every UPI/IMPS/NEFT-24x7/RTGS/ATM/POS hit is OLTP.

78 Real-time processing?

a sub-class of OLTP where the response must be delivered within a strict, deterministic time bound (milliseconds) — UPI's 30-second timeout, IMPS, RTGS, ATM authorisation.

79 Centralised vs Distributed?

in centralised, several "dumb terminals" share one central mainframe (classic 1970s model). In distributed, multiple machines connected over a network share the load — this is today's CBS + ATM-switch + UPI-switch architecture.

80 Record Locking?

when two users try to update the same record at the same time, the record is locked for the second user until the first user's transaction completes. Prevents the "lost update" problem in CBS.

81 Check-pointing & logging?

the system continuously logs the state of the master file before and after each update, so that on failure the system can roll back or roll forward to a consistent state. Foundation of ACID transactions (Atomicity, Consistency, Isolation, Durability) — covered fully in the DBMS chapter.

82 Public cloud?

infrastructure hosted at the vendor's premises, shared by many tenants. Examples: AWS, Azure, GCP, Oracle Cloud.

83 Private cloud?

infrastructure dedicated to a single organisation — either on-premise or with a single-tenant vendor. More secure, more expensive.

84 Hybrid cloud?

public + private together — typical large bank uses private cloud for CBS/customer data and public cloud for analytics, sandbox & test workloads.

85 Community cloud?

shared among a community of organisations with common concerns (e.g., a group of co-operative banks sharing a regulated cloud).

86 Infrastructure as a Service (IaaS)?

vendor offers raw hardware-level services: virtual machines, block storage, virtual networks. Example: AWS EC2, Azure VMs.

87 Platform as a Service (PaaS)?

vendor offers a runtime environment for developers to easily build, test, deploy and run applications without managing the underlying OS or middleware. Example: AWS Elastic Beanstalk, Google App Engine.

88 Software as a Service (SaaS)?

vendor offers a ready-to-use software application on subscription / pay-per-use. Examples: Salesforce, Microsoft 365, Gmail, Zoom.

89 Security & privacy?

valuable enterprise data resides outside the corporate firewall.

90 Latency?

physical distance between data centre and end-user adds delay.

91 Vendor lock-in?

porting workload from one cloud to another is non-trivial.

92 Regulatory & data-localisation?

RBI requires payment data to be stored only in India (April 2018 directive).

93 Network and Storage Virtualization?

virtual SANs / NVMe-oF; greater ease of use, security and scalability without buying more hardware.

94 Desktop Virtualization (VDI)?

desktop data is stored on a centralised / remote server, not on the client device. Users access their virtual desktop from any thin client. A staple in many banks for branch desktops and call-centre seats.

95 Containerisation?

Docker + Kubernetes — even lighter than VMs; OS-level virtualization. Now the standard for modern banking microservices.

96 Presentation tier?

what the user sees: branch teller screen, mobile-banking app, net-banking portal, ATM screen, POS terminal.

97 Application tier?

the CBS engine itself (Infosys Finacle, Oracle FLEXCUBE, TCS BaNCS, etc.) — runs the business logic: account opening, deposit, withdrawal, interest calc, GL posting, EOD/BOD. Sits alongside channel managers that handle UPI / IMPS / NEFT / RTGS / mobile / net / ATM channels and route them into the…

98 Database tier?

an RDBMS (typically Oracle, DB2 or MS-SQL) holding the single, golden, real-time customer & account database. Data is replicated synchronously to the Disaster Recovery (DR) site so that RPO ≈ 0 and RTO is within hours, in line with the RBI Master Direction's BCP/DR expectations.

99 "Any-where, any-time, any-channel" banking?

the customer record sits in one central DB; any branch or channel sees the same balance.

100 Real-time updates?

UPI debit hits the GL within seconds.

101 Centralised compliance?

KYC, AML, FATCA, CTR/STR all sit on the same data.

102 Lower cost?

branches do not run their own servers; centralised hardware and licences.

103 RBI Master Direction on Outsourcing of IT Services (Apr 10, 2023)?

sets the framework for outsourcing including cloud services. Banks may use public, private, hybrid or community cloud but must conduct enhanced due diligence, ensure data residency in India for payment data (April 6, 2018 directive), audit rights, exit strategy and a board-approved cloud-adoption…

104 RBI's "Cloud Facility for Indian Financial Sector"?

RBI, through IFTAS (Indian Financial Technology and Allied Services), is operationalising a community / sovereign cloud for the Indian financial sector, primarily targeted at small / co-operative banks and NBFCs that cannot run their own data centres. Public-cloud adoption by large PSBs continues…

105 Hardware refresh & green computing?

most large Indian PSBs have now migrated CBS production storage to enterprise SSD/NVMe (5–20× faster than HDD), in line with the IT MD's expectations on currency and capacity planning. Virtualization and containerisation (Docker + Kubernetes) are the standard data-centre architecture, materially…

106 Unicode in regional-language banking?

RBI's regional-language ATM/UPI/mobile-banking initiatives rely on Unicode (UTF-8) to deliver banking in 13+ Indian languages including Hindi, Marathi, Bengali, Tamil, Telugu, Kannada, Gujarati, Punjabi, Malayalam, Odia, Assamese, Urdu — and the new Hello UPI / Conversational UPI (NPCI, 2024)…

107 (True/False) The Mill in Babbage's Analytical Engine corresponds to today's ALU?

TRUE

108 (True/False) John von Neumann proposed the stored-program concept in 1946?

TRUE

109 (True/False) The first generation of computers used transistors as the switching device?

FALSE — 1st gen used vacuum tubes; transistors belong to 2nd gen.

110 (True/False) FORTRAN and COBOL were developed during the second generation of computers?

TRUE

111 (True/False) The microprocessor chip is a defining feature of the third generation of computers?

FALSE — Microprocessor defines the fourth generation.

112 (True/False) In a digital computer, all data is ultimately stored and processed in binary (base 2)?

TRUE

113 (True/False) Cache memory is slower than main RAM?

FALSE — Cache is much faster (and smaller) than main RAM and sits between CPU and RAM in the hierarchy.

114 (True/False) SSDs typically have lower latency than HDDs because they have no moving parts?

TRUE

115 (True/False) In batch processing, transactions are processed immediately as they are entered?

FALSE — That is on-line / real-time processing. Batch groups transactions for delayed, scheduled processing.

116 (True/False) Record Locking in on-line processing prevents two users from updating the same record simultaneously?

TRUE

117 (True/False) Public cloud is generally more secure and more expensive than a private cloud?

FALSE — Private cloud is generally more secure and more expensive than public; public is shared.

118 (True/False) De Morgan's Law states that NOT (A AND B) = (NOT A) OR (NOT B)?

TRUE

119 (True/False) The hexadecimal equivalent of the binary number 1101 0110 is D6?

TRUE

120 (True/False) UTF-8 is a fixed-width 4-byte Unicode encoding?

FALSE — UTF-8 is variable width (1–4 bytes); UTF-32 is the fixed 4-byte form.

121 (True/False) The RBI Master Direction on IT Governance, Risk, Controls and Assurance Practices is dated 7 November 2023 and became effective from 1 April 2024?

TRUE

122 1 byte — Figure / Rule / Where Used?

Figure / Rule: 8 bits; Where Used: Storage size

123 1 KB / MB / GB / TB / PB — Figure / Rule / Where Used?

Figure / Rule: 2¹⁰ / 2²⁰ / 2³⁰ / 2⁴⁰ / 2⁵⁰ bytes; Where Used: Memory & storage

124 Hex digits — Figure / Rule / Where Used?

Figure / Rule: 0–9, A(10), B(11), C(12), D(13), E(14), F(15); Where Used: Memory dumps, MAC addr

125 Binary Hex — Figure / Rule / Where Used?

Figure / Rule: Group 4 bits from the right; Where Used: Quick conversion

126 Binary Octal — Figure / Rule / Where Used?

Figure / Rule: Group 3 bits from the right; Where Used: Quick conversion

127 Two's-complement of N — Figure / Rule / Where Used?

Figure / Rule: Invert all bits + 1; Where Used: Signed integer arithmetic

128 ASCII size — Figure / Rule / Where Used?

Figure / Rule: 7-bit (128 chars), extended 8-bit (256); Where Used: Western text

129 UTF-8 size — Figure / Rule / Where Used?

Figure / Rule: Variable 1–4 bytes/char; Where Used: Web, regional-language banking

130 De Morgan's Law — Figure / Rule / Where Used?

Figure / Rule: ¬(A·B)=Ā+B̄ ; ¬(A+B)=Ā·B̄; Where Used: Boolean algebra

131 Generations — Figure / Rule / Where Used?

Figure / Rule: 1-Vac, 2-Trans, 3-IC, 4-µP/VLSI, 5-ULSI/AI; Where Used: History

132 CPU sub-units — Figure / Rule / Where Used?

Figure / Rule: ALU + CU + Registers; Where Used: Hardware

133 Memory hierarchy — Figure / Rule / Where Used?

Figure / Rule: RegCacheRAMSSDHDDTape; Where Used: Performance vs cost

134 Cloud service models — Figure / Rule / Where Used?

Figure / Rule: IaaS / PaaS / SaaS; Where Used: Cloud taxonomy

135 Cloud deployment models — Figure / Rule / Where Used?

Figure / Rule: Public / Private / Hybrid / Community; Where Used: Cloud taxonomy

136 RBI IT Governance Master Direction — Figure / Rule / Where Used?

Figure / Rule: Dt 7-Nov-2023, effective 1-Apr-2024; Where Used: Governance

137 RBI Outsourcing of IT Services MD — Figure / Rule / Where Used?

Figure / Rule: Dt 10-Apr-2023; Where Used: Cloud / outsourcing

138 RBI payment-data localisation — Figure / Rule / Where Used?

Figure / Rule: Circular dated 6-Apr-2018; Where Used: Data residency

139 COMPUTER?

"Commonly Operated Machines Used in Technical and Educational Research."

140 ACU-M for CPU?

ALU, CU, Memory/Registers.

141 "Group 4 for hex, 3 for octal, always from the right"?

for binary conversion.

142 "Break the bar and flip the sign"?

De Morgan's Law shortcut.

143 IPaaSaaS — I-P-S?

IaaS, PaaS, SaaS (in increasing level of abstraction; you give up control as you go up).

One-linersInformation Systems Audit