KeyKOS

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Web site: cap-lore.com/CapTheory/KK/
Origin: USA
Category: Microkernel, Others
Desktop environment: CLI
Architecture: IBM S/370, IBM Mainframe
Based on: GNOSIS
Wikipedia: KeyKOS
Media: Install
The last version | Released: ? | ?

KeyKOS – an operating environment for S/370 computers which provides a high level of security, reliability, performance, and productivity. It allows emulation of other environments such as VM, MVS, and POSIX.

When Tymshare started work on KeyKOS in the early 1970s, there were solid business requirements justifying the project. With the price of main storage dropping, applications were too tightly bound to disk storage. Because Tymshare’s systems were accessed from around the world, continuous operation was a requirement. Existing systems were prone to failure from many causes, both hardware and software. They did not recover from these failures gracefully. These systems required significant operator intervention in both normal operation and during recovery. They did not provide the security needed to allow competing organizations to share programs and data in a controlled manner where it made economic and social sense.

Because of these deficiencies, Tymshare decided its best option was to build a system of its own. This system had a number of design goals including: high security, high reliability, economical processing of high transaction volumes, and enhanced productivity for managers, programmers, users, operators, and hardware.

KeyKOS provides persistent virtual address spaces where programs may keep data. The system caches frequently referenced data in main storage. When several processes are accessing the same data, for example the CMS “S” disk, the data blocks involved are likely to already in main storage, improving access times. Only one copy will be maintained in main storage, improving storage utilization. Persistent virtual storage allows the kernel to globally optimize disk arm movement and rotational latency. The KeyKOS implementation also provides complete separation of physical and logical DASD management. No unprivileged program is aware of the type or configuration of real DASD in the system.

KeyKOS has a system-wide checkpoint which periodically saves the state of the entire system. If a system outage occurs, the system will restart from the last checkpoint with all data and processes in a consistent state as of that checkpoint. The KeyTXF transaction processing system will recover database updates to the point of failure. Should a CPU fail, the DASD can be shared with or switched to a backup CPU to quickly restore service by restarting from the last checkpoint.

Data mirroring stores multiple copies of data for reliability and performance. The KeyKOS system continues to operate if a mirrored disk fails. When the disk is repaired, or a replacement disk is formatted and brought online, the mirrored data is automatically restored to that disk. Performance is enhanced by having several paths to a particular piece of data. The full function of the system is available in essentially any S/370 computer language. A standard invocation protocol permits high level languages to invoke low level function and low level languages to invoke high level function, enhancing the usefulness of all languages.

The KeyKOS system is designed for unattended operation. The only common operator functions are mounting tapes and servicing the printer.

The KeyKOS system is designed for continuous operation. Full system backup dumps may be taken while the system is running. When a dump has completed, the backup tapes contain an image of all data and processes in the system at a consistent instant of time. avoiding inconsistency in the data. These “tape checkpoints” are conceptually independent of the physical DASD type or configuration. They may be restored to different physical devices if necessary.

KeyKOS/370 runs on System/370-compatible single processor CPUs. It currently supports 3330, 3350, and 3380 count key data format disks and 3370 FBA format disks. System software includes the context switcher and two command systems.

Copyright © 1985, 1987, 1988, 1990 Key Logic. All rights reserved.
Permission to reproduce and redistribute this document in paper or electronic form is hereby granted, provided that this copyright notice remains intact.

KeyKOS is a predecessor of the EROS and its successors are CapROS and Coyotos operating systems.

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CapROS

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Web site: www.capros.org
Origin: USA
Category: Microkernel, Others
Desktop environment: CLI
Architecture: x86, ARM
Based on: EROS
Wikipedia:
Media: Install
The last version | Released: 1 | May 2, 2005

CapROS (Capability-based Reliable Operating System) – an experimental capability-based operating system, based on EROS, KeyKOS, and Gnosis. Ports exist for the Intel IA-32 and ARM9 architectures. CapROS is an operating system that merges some very old ideas about capabilities with some newer ideas about performance and resource management. The result is a small, secure, real-time operating system that provides orthogonal persistence.

It is a pure capability-based system that features automatic persistence of data and processes, even across system reboots. Capability systems naturally support the principle of least authority, which improves security and fault tolerance.

The CapROS project is led by Charles Landau. It was under developed by Strawberry Development Group with funding from DARPA and others.

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CapROS source archive 43.7MB.tgz
md5sum: d27038d2b461eb7c772a60fb261cd0a8

 

Coyotos

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Web site: www.coyotos.org (not active)
Origin: USA
Category: microkernel
Desktop environment: CLI
Architecture: x86
Based on: Independent
Wikipedia (FR): Coyotos
Media: Install
The last version | Released: ? | 2010

Coyotos – a secure, microkernel-based operating system that builds on the ideas and experiences of the EROS project, that itself is the successor of KeyKOS, itself coming from GNOSIS (Great New Operating System In the Sky). Much of the code developed for EROS will migrate directly to Coyotos. The EROS system that was created at the University of Pennsylvania and Johns Hopkins University.

Coyotos will be written in BitCee. BitC is a SystemProgramming language that combines the “low-level” nature of C with the semantic rigor of Scheme or ML. BitC was designed by careful selection and exclusion of language features in order to support proving properties (up to and including total correctness) of critical systems programs.

The Coyotos project has several objectives:
– Correct some of the shortcomings of the earlier EROS design.
– Demonstrate that an atomic kernel design scales up as well as down. We are planning to bring up versions of Coyotos on large-scale multiprocessors.
– Provide an efficient linux compatibility environment for use as a transitional runtime system, so that we can explore adapting applications to a more secure API foundation.
– (Eventually) Construct the kernel and key utilities in a new systems programming language (BitC) with a well-defined, mechanically-specified semantics. This will allow us to formally verify security and correctness properties of the system and its key utilities.
– Develop the proving technology necessary to do useful verification about a project of this sort.

The primary developer of EROS was Jonathan S. Shapiro, who is also a driving force behind Coyotos and the BitC programming language.
Since March 2010, the main development effort has been on the BitC language being designed for use in Coyotos: as of April 2016, the last change to Coyotos was in June 2010.

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