ITA flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Fetch-Decode-Execute Cycle

The repeating CPU instruction cycle: fetch the instruction addressed by the program counter, decode its opcode, execute it in the ALU or control unit, then store the result and advance the counter.

Volatile vs Non-Volatile Memory

Volatile memory such as RAM and cache loses its contents when power is removed. Non-volatile memory such as ROM, flash, and disk retains data across power cycles.

RAID 5

Disk striping with single distributed parity. It survives one drive failure, requires at least three drives, and offers usable capacity of N minus one drive.

Hypervisor

Software that creates and runs virtual machines by partitioning physical CPU, memory, and I/O. Type 1 runs directly on hardware; Type 2 runs on a host operating system.

Kernel Mode vs User Mode

The kernel executes in privileged mode with direct hardware access. Applications run in restricted user mode and request kernel services through system calls, preventing faulty programs from corrupting the system.

Virtual Memory and Paging

The OS maps logical addresses to physical frames using page tables. A page fault loads a missing page from disk; excessive faulting that outpaces useful work is called thrashing.

Round Robin Scheduling

A preemptive CPU scheduling algorithm that gives each ready process a fixed time slice in rotation. It is fair and responsive but adds overhead from frequent context switches.

Clean Install vs Upgrade

A clean install wipes the target volume and installs fresh, removing existing data and settings. An upgrade preserves files, settings, and applications while replacing the OS version.

Private IPv4 Ranges

Non-routable address blocks reserved for internal networks: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. They require NAT to reach the public internet.

TCP Three-Way Handshake

Connection setup using SYN, SYN-ACK, and ACK segments. It synchronizes sequence numbers and confirms both hosts are reachable before data transfer begins.

Subnet Host Calculation

Usable hosts equal two raised to the number of host bits minus two. A /24 mask leaves eight host bits, giving 256 addresses and 254 usable host addresses.

DHCP DORA Process

Four-step address assignment: Discover broadcast from client, Offer from server, Request from client accepting the offer, and Acknowledge confirming the lease.

Symmetric vs Asymmetric Encryption

Symmetric encryption uses one shared key and is fast, suitable for bulk data. Asymmetric encryption uses a public/private key pair, enabling secure key exchange and digital signatures.

Incremental vs Differential Backup

Incremental backups copy changes since the last backup of any type. Differential backups copy changes since the last full backup, so differential restores need only the full plus one differential.

Multi-Factor Authentication

Authentication requiring two or more distinct factor types: something you know, something you have, or something you are. Two passwords do not qualify as multifactor.

Principle of Least Privilege

Granting users and processes only the permissions required for their tasks. It limits the damage from compromised accounts, mistakes, and malicious insider activity.

Troubleshooting Methodology

A structured sequence: identify the problem, establish a theory, test it, form a plan of action, verify full functionality, and document findings for future reference.

Safe Mode

A diagnostic boot that loads minimal drivers and services. If a fault disappears in safe mode, the cause is likely a third-party driver or startup program.

Escalation Criteria

Conditions that move a ticket to a higher support tier: unresolved after defined effort, need for privileged access, or impact on multiple users or a production service.

Ping and Traceroute

Ping tests reachability and round-trip time to a host using ICMP echo. Traceroute lists each router along the path, revealing where packets stop or slow.

ACID Properties

Transaction guarantees: Atomicity (all or nothing), Consistency (valid state), Isolation (concurrent transactions do not interfere), and Durability (committed data survives failure).

Primary Key vs Foreign Key

A primary key uniquely identifies each row in a table. A foreign key is a column referencing another table's primary key, enforcing referential integrity between related tables.

Third Normal Form

A table is in 3NF when it is in 2NF and no non-key attribute depends transitively on the primary key, eliminating redundancy that causes update anomalies.

RPO and RTO

Recovery point objective is the maximum tolerable data loss measured in time. Recovery time objective is the maximum tolerable downtime before service must be restored.

HTTP Status Code Classes

Two hundred series indicate success, three hundred series indicate redirection, four hundred series indicate client errors such as 404 not found, and five hundred series indicate server errors.

REST Constraints

Representational state transfer uses resource URLs, standard HTTP verbs, stateless requests, and representations such as JSON. Each request carries all information needed to process it.

SQL Injection Prevention

Use parameterized queries or prepared statements so user input is treated as data, not executable SQL. Server-side validation and least-privilege database accounts add defense in depth.

Model-View-Controller

An architectural pattern separating data and business rules (model), presentation (view), and request handling (controller), allowing each layer to change independently.

Incident vs Problem

An incident is an unplanned service interruption restored quickly to minimize impact. A problem is the underlying cause, investigated through root cause analysis to prevent recurrence.

SLA vs OLA

A service level agreement defines commitments to the customer, such as availability and response time. An operational level agreement is an internal commitment between teams supporting that SLA.

Change Advisory Board

A group that assesses risk, impact, and scheduling for normal changes before approval. Standard changes are pre-approved, and emergency changes use expedited approval paths.

Priority Formula

Priority is derived from impact multiplied by urgency. Impact measures the breadth of effect and urgency measures how quickly the business needs resolution, setting response order against SLAs.