DOCUMENT ID: 1204-02 SYNOPSIS: Layers of the Virtual Memory System OS RELEASE: 2.4 PRODUCT: Solaris KEYWORDS: layers virtual memory address space segment vnode driver DESCRIPTION: Layers of the Virtual Memory System SOLUTION: * SunOS system calls and services - the user interface to the kernel's VM management structures and procedures. The predominant system call is mmap(), and read() and write() calls are implemented through an internal version of mmap(). * Address space - state information about a process's address space is maintained through a linked list of contiguous address mappings arranged by virtual address. * Segment drivers - the address space mappings are termed segments, and operations on segments are implemented through a set of segment drivers. * vnode drivers - the vnode object managers are responsible for creating and initializing a request page, which may include interfacing with the physical I/O layer to obtain the data. * Physical I/O - the machine-dependent layer that manages backing store according to the physical characteristics of the peripheral device. * Hardware address translation (HAT) - the HAT layer is the machine-dependent code that manages the hardware translations to pages in the machine's MMU. DATE APPROVED: 09/18/95