# Abbreviations and Acronyms

## General

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| ABI    | Application Binary Interface                 |
| API    | Application Programming Interface            |
| ASCII  | American Standard Code for Information       |
|        | Interchange                                 |
| BIOS   | Basic Input/Output System                    |
| CLI    | Command Line Interface                       |
| CPU    | Central Processing Unit                      |
| DMA    | Direct Memory Access                         |
| ELF    | Executable and Linkable Format               |
| FHS    | Filesystem Hierarchy Standard                |
| FS     | Filesystem                                  |
| FOSS   | Free and Open Source Software                |
| GNU    | GNU's Not Unix                              |
| GPU    | Graphics Processing Unit                     |
| GUI    | Graphical User Interface                     |
| I/O    | Input/Output                                 |
| IPC    | Inter-Process Communication                  |
| ISO    | International Organization for               |
|        | Standardization                             |
| KISS   | Keep It Simple, Stupid                       |
| LTS    | Long-Term Support                            |
| MMU    | Memory Management Unit                       |
| OS     | Operating System                             |
| POSIX  | Portable Operating System Interface          |
| RAM    | Random Access Memory                         |
| ROM    | Read-Only Memory                             |
| SMP    | Symmetric Multiprocessing                    |
| TTY    | Teletypewriter                               |
| UEFI   | Unified Extensible Firmware Interface        |
| UI     | User Interface                               |
| UUID   | Universally Unique Identifier                |
| VM     | Virtual Machine                              |
| VMM    | Virtual Machine Monitor                      |

## Kernel and Low-Level

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| CFS    | Completely Fair Scheduler                    |
| GFP    | Get Free Page (allocation flags)             |
| HRT    | High Resolution Timer                        |
| IRQ    | Interrupt Request                            |
| ISR    | Interrupt Service Routine                    |
| KASLR  | Kernel Address Space Layout Randomization    |
| Kbuild | Kernel build system                          |
| Kconfig| Kernel configuration system                  |
| LKM    | Loadable Kernel Module                       |
| MM     | Memory Management subsystem                  |
| NMI    | Non-Maskable Interrupt                       |
| NUMA   | Non-Uniform Memory Access                    |
| OOM    | Out Of Memory                                |
| RCU    | Read-Copy Update                             |
| RT     | Real-Time                                    |
| TLB    | Translation Lookaside Buffer                 |
| VFS    | Virtual Filesystem                           |

## Filesystems and Storage

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| ACL    | Access Control List                          |
| Btrfs  | B-Tree Filesystem                            |
| EXT4   | Fourth Extended Filesystem                   |
| FAT    | File Allocation Table                        |
| GPT    | GUID Partition Table                         |
| MBR    | Master Boot Record                           |
| NFS    | Network File System                          |
| RAID   | Redundant Array of Independent Disks         |
| tmpfs  | Temporary Filesystem                         |

## Programming and Toolchain

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| ASM    | Assembly Language                            |
| C99    | ISO C Standard (1999)                        |
| GCC    | GNU Compiler Collection                      |
| GDB    | GNU Debugger                                 |
| GLIBC  | GNU C Library                                |
| LD     | Linker                                       |
| LIBC   | Standard C Library                           |
| OBJ    | Object File                                  |
| PLT    | Procedure Linkage Table                      |
| GOT    | Global Offset Table                          |
| REPL   | Read-Eval-Print Loop                         |

## Userspace and System

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| DBus   | Desktop Bus (IPC system)                     |
| ENV    | Environment Variable                         |
| INIT   | Initial process (PID 1)                      |
| PAM    | Pluggable Authentication Modules             |
| PID    | Process Identifier                           |
| PPID   | Parent Process Identifier                    |
| PROCFS | Process Filesystem (/proc)                   |
| SYSFS  | System Filesystem (/sys)                     |
| UID    | User Identifier                              |
| GID    | Group Identifier                             |

## Shell and Scripting

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| BASH   | Bourne Again SHell                           |
| FD     | File Descriptor                              |
| PWD    | Present Working Directory                    |
| SH     | Bourne Shell                                 |
| STDIN  | Standard Input                               |
| STDOUT | Standard Output                              |
| STDERR | Standard Error                               |

## Networking

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| ARP    | Address Resolution Protocol                  |
| DNS    | Domain Name System                           |
| HTTP   | Hypertext Transfer Protocol                  |
| HTTPS  | Hypertext Transfer Protocol Secure           |
| ICMP   | Internet Control Message Protocol            |
| IP     | Internet Protocol                            |
| IPv4   | Internet Protocol Version 4                  |
| IPv6   | Internet Protocol Version 6                  |
| MAC    | Media Access Control (address)               |
| NAT    | Network Address Translation                  |
| OSI    | Open Systems Interconnection                 |
| TCP    | Transmission Control Protocol                |
| UDP    | User Datagram Protocol                       |
| UNIX   | Unix Domain Socket                           |

## Hardware

| Abbrev | Meaning                                      |
|--------|----------------------------------------------|
| ACPI   | Advanced Configuration and Power Interface   |
| APIC   | Advanced Programmable Interrupt Controller   |
| ATA    | Advanced Technology Attachment               |
| CMOS   | Complementary Metal-Oxide Semiconductor      |
| I2C    | Inter-Integrated Circuit                    |
| PCI    | Peripheral Component Interconnect            |
| PCIe   | Peripheral Component Interconnect Express    |
| PS/2   | Personal System/2                            |
| SATA   | Serial ATA                                   |
| USB    | Universal Serial Bus                         |
| VGA    | Video Graphics Array                         |