frame
also: packet, page frame, Ethernet frame
A fixed-size block of data transmitted over a network, consisting of a header, payload, and trailer. In the kernel, a frame also refers to a fixed block of memory in virtual address space.
In networking, a frame is the fundamental unit of data at Layer 2 (Data Link Layer) of the OSI model. It wraps your data with hardware-specific information like source and destination MAC addresses, error-checking codes, and frame delimiters. When you send data across Ethernet or Wi-Fi, it's broken into frames for reliable transmission.
Example: An Ethernet frame for a simple HTTP request might look like: [MAC header][IP header][TCP header][HTTP data][CRC checksum]. Each frame is typically 1500 bytes (MTU) or smaller.
In kernel memory management, a frame (or page frame) is a fixed-size block of physical RAM, usually 4KB on x86 systems. The kernel tracks which process owns each frame and whether it's free, in use, or reserved. This allows the kernel to manage virtual memory by mapping virtual pages to physical frames.