PTS ROM-DOS

Technical documentation is available.

Today for industrial embedded computers are used Intel processors or processors compatible with them. Usually the architecture of computer differs from usual architecture of PC by absence of hard and floppy disks and presence of Flash-memory and several special devices. Advanced demand for the safety and the necessity of service of the non-standard equipment require changes in the order of initialization and the work of BIOS. The version of PTS ROM-DOS and a special module PTS-BIOS were created to satisfy the request. The aim of the project was the development of a home modificative operating system which includes BIOS and is placed in ROM of industrial computers. The system is designed to build the real-time systems and to provide the access to resources of the computer which has several constructive peculiarities. It is intended for the working in hard conditions of exploitation with the inevitable obstacles and impossibility of the continual service.

Components of system

• Loader of BIOS
  is the only non-modifiable part of the system and it is used for the primary initialization of a computer and for the loading of the modifiable part of BIOS.
• BIOS
  is a part of the operating system, which provides the initialization and testing of the equipment and the work with the equipment at the low level (including emulation of the keyboard, the display and disks on the present equipment). It also provides functions of standard BIOS.
• DOS
  is a variant of the well-known operating PTS-DOS, adapted under conditions of the limited resources.
• DOS command interpreter.
• Extra utilities
  are used for the changing of configuration parameters of the equipment and the system, for the modification of the information in Flash-memory and for providing distance service of the embedded computer.

Meanings of increasing of safety of the system

• Supporting of watchdog timer.
  watchdog timer is the most simple meaning of preventing hanging up of the system because of malfunction of the equipment or because of a program error. It provides restart of a computer if the program didn't clear the watchdog timer during certain interval of time. PTS-BIOS and PTS ROM-DOS provide starting of the watchdog timer at the very beginning of initialization and its service during its working.
• Accumulation and output of the diagnostics after request.
  After every restart the system remembers the numbers of reached control points and results of tests. Later the results can be analyzed to detect faults and malfunctions in the software.
• Calculating of the CRCs of code and most important data.
  Testing of CRCs provides detecting of malfunctions of storages and correct transfer of information.
• Detecting errors in the disk system.
  Operating system uses error correction codes for the timely detecting of damaged information and tries to restore it if possible. It is specially important for the Flash-disk, which is used to lasting storing of data.
• An opportunity of modification of BIOS and DOS.
  As soon as configuration of the system provides choosing from where BIOS and DOS will be loaded in the case of occurring of ROM malfunctions, in the case of errors in the software or in the case of damaged equipment, there always is an opportunity to use versions of BIOS and DOS, transmitted through the channel or kept on the Flash-disk.

Under the operating system PTS ROM-DOS with the help of real-time multitasking environments (accessible in source codes, which are necessary for the certification) as RT-kernel or CTask-RT excellently work real-time applications. The package of PTS ROM-DOS includes a special tool for their creating - SRV-constructor.