Generic Block Interface Reference Manual

Contents

• Introduction
  • IDL Interface
  • Client Library
  • Server Library
• Client Library API Documentation
  • Open/Close Driver Instances
  • Create/Close/Start Real-Time Streams
  • Block Requests
  • Driver Setup
  • Initialization
• IDL Interface Documentation
  • Driver Interface
  • Request Interface
  • Notification Interface

Introduction

The Generic Block Interface provides the interface used by DROPS block device drivers. The interface provides both best-effort and real-time (stream) block requests.

IDL Interface

The Generic Block IDL interface is an asynchronous interface. That means clients do not block until a request is processed by a driver. Instead, clients immediately return after sending the request to a driver and get a notification if a request is processed at a later time. The Generic Block Interface consists of three IDL interfaces, a Request Interface to send requests to a driver, a Notification Interface to wait for a notification from a driver and a Driver Interface to setup the other interfaces.

Client Library

The client library (libgeneric_blk) implements several functions to use block device drivers. In particular, it implements a mechanism to wait for the notifications from a driver. The library uses a separate thread to wait for the notifications from a driver and notifies the client by either executing a callback function or incrementing a semaphore which both can be specified by the client. The same mechanism is used by the library to provide a synchronous request function.

Server Library

The server library (libgeneric_blk-server) provides the skeleton functions generated by the IDL compiler which must be used to implement a block device driver.