Remote Initial Program Load
Remote Initial Program Load (abbreviation: RIPL; German: Remote initial program load) - Refers to the process of starting an operating system over the network from a server on which a RIPL service is enabled, which LAN under the Network Operating System Manager, LAN Server, Windows NT Server and Novell NetWare is supported.
IBM LAN Server
The IBM LAN Server provides information about the 802.2/DLC-Protokoll the clients ( so-called RIPL requesters ) the possibility of the operating systems DOS or OS / 2 on the local network ( mostly token ring) to load.
The server monitors the local network here and reviewed the requests from individual stations with the entries in the mapping table RPL.MAP.
RPL and DOS
During the initial phase of the DOS operating system, usually result in the problem that the previously loaded over the network RPL code ( RPL Remote Program Load) in the not yet allocated conventional memory is (typically on the upper end ) still can not be overwritten, but while the freshly loaded operating system its own administrative organizations has yet to build. Normally, the RPL code, thereby protecting against overwriting by the operating system that it assumes, among other things, control of the INT 12 BIOS function that is called from DOS to determine existing real-mode memory size.
This brings several difficulties, in particular on modern DOS systems with them, in which free memory areas in the adapter area or in the address space of the video RAM can be used for driver and parts of the operating system to provide DOS applications more free conventional memory available.
A few different tricks these problems can be circumvented to some extent, but the RPL code needs to dig deep to intervene in the internals of the loaded operating system, which does not work in all cases clean, especially if also are other loaded drivers in the game that similar methods to use.
To hedge the procedure examines DOS MS-DOS/PC DOS 5.0 and DR DOS 6.0 startup code of the INT 2F interrupt vectors according to the identifier " RPL " and calls if necessary. the INT function 2F/AX = 4A06h on to learn the true amount of memory available from the RPL code and this practically take out the back door to the list of allocated DOS memory areas and thus to encapsulate against unauthorized access by others. However, the RPL code is still responsible for at the end of the boot phase to be removed properly from the system.
DR DOS only supports the RPL interface described above also has an advanced form of the method called RPLOADER that offers more flexibility. Detects the presence of a DR DOS RPL codes with the identifier " RPLOADER " ( instead of " RPL "), then sends the DOS BIOS additionally after reaching certain stages within the boot phase, special INT 2F/AX = 12FFh/BX = 0005h Broadcasts ( to reduce not " lying in the way" to the later useful for DOS applications memory by the RPL code) the RPL code to give this the opportunity suitable to Relocate in memory to plug even deeper into the system or additional " cleanup " to perform or to cleanly remove from the system. To avoid Besides increasing the compatibility of being able to handle certain actions via a defined interface and at defined times within the boot phase, a reduction and fragmentation of the memory and thus to increase the usable for applications memory and the RPL code after the boot phase clean to remove from the system, the interface DR DOS can also be used to load as a task under the host operating systems such as Concurrent DOS.
History
The remote loading for DOS workstations Images was in 1990 supported by the IBM LAN Server 1.2 through service PCDOSRPL. Since the LAN Server 2.0 (1992 ) it was also possible to use OS/2-Stationen (version 1.30.1 ).