PROFILPELAJAR.COM

V
Developer	David Cheriton
Written in	C
OS family	Distributed operating system
Working state	Discontinued
Initial release	1981; 44 years ago
Latest release	Final / 1988; 37 years ago
Marketing target	Research
Available in	English
Update method	Compile from source code
Platforms	Workstations:; SUN, MicroVAX, DEC Firefly
Kernel type	Microkernel
Default; user interface	VGTS
License	Stanford University
Preceded by	Thoth, Verex

The V operating system (sometimes written V-System) is a discontinued microkernel distributed operating system that was developed by faculty and students in the Distributed Systems Group at Stanford University from 1981 to 1988, led by Professors David Cheriton and Keith A. Lantz.^[1] V was the successor to the Thoth operating system and Verex kernel that Cheriton had developed in the 1970s.^[2]^[3] Despite similar names and close development dates, it is unrelated to UNIX System V.

Features

The key concepts in V are multithreading and synchronous message passing. The original V terminology uses process for what is now commonly called a thread, and team for what is now commonly called a process consisting of multiple threads sharing an address space. Communication between threads in V uses synchronous message passing, with short, fixed-length messages that can include access rights for the receiver to read or write part of the sender's address space before replying. The same message-passing interface is used both between threads within one process, between threads of different processes within one machine, and between threads on different machines connected by a local Ethernet.^[4] A thread receiving a message is not required to reply to it before receiving other messages; this distinguished the model from Ada rendezvous.

One common pattern for using the messaging facility is for clients to send messages to a server requesting some form of service. From the client side, this looks much like a remote procedure call (RPC). The convenience of an automatic stub generator was lacking, but in contrast, the client can pass one parameter by reference, which is not possible with other RPC implementations. From the server side the model differs more from RPC, since by default all client requests are multiplexed onto one server thread. The server is free to explicitly fork threads to handle client requests in parallel, however; if this is done, the server-side model is much like RPC too.

V was never an end in itself for the Stanford group; rather, it was used as a vehicle for many different research projects in distributed operating systems and networking. Much like other operating system efforts of its day (such as Sprite), V was a complete system that was mostly self hosting. Many students ran V as the only operating system on their diskless SUN workstations or MicroVAX workstations. Compiles could be done either on V, or on VAX Unix machines that provided file service in a more stable environment than the ever-changing research system.

V did have some notable impacts. After the initial implementation on one computer, the Versatile Message Transaction Protocol (VMTP) was developed to extend the send-receive-reply system call semantics over a local area network.^[5]^[6] The protocol included multicast support developed by Steve Deering as a graduate student in the group. The Internet Protocol layer to support this evolved into the IP multicast standard.^[1]^[7]

The V-System was used for graphical user interface (GUI) research. The Virtual Graphics Terminal Service (VGTS) provided a modular windowing system for both local and remote applications.^[8] The little-known W Window System got its name because it was first hosted on the V operating system, and the better-known X Window System in turn got its name because its first version was based partly on W.^[9]

V also spawned another pure microkernel effort at Apple Computer known as Vanguard, which added a number of improvements to the basic system.^[10] Vanguard later disappeared in a reorganization.

The Tektronix VM700 television measurement instrument was developed in a networked V environment in the late 1980s and ran a lightly modified version of the V operating system; this device was manufactured and sold for many years.

Ridge Computers' Ridge Operating System (ROS) was a commercial system based on Stanford's V-System.^[11]

Commands

The following is a list of workstation commands that are supported by the V operating system version 6.0 command-line interface.^[12]

addcorr
amaze
ar
biopsy
bitcompile
bits
boise
build
cat
cc68
cd
checkers
checkexecs
ci
clear
clock
co
cp
cpdir
cx
dale
date
debug
debugvgts
define
delcorr
delexec
destroy
diff
do
domake
dopar
doseq
draw
echo
fexecute
freemem
gftodvi
gftyoe
grep
hack
ident
instances
internetserver
iphost
killprog
listdir
listdesc
login
logout
mail
memserver
mf
migrateprog
mon
name
newterm
pagemode
password
pc68
pwd
pwx
Q
query
queryexec
ranlib68
rcs
rcsdiff
rcsmerge
rename
rlog
rm
sed
serial
show
sleep
sort
startexec
storagestats
stuffboot
tail
talk
telnet
telnetserver
testexcept
timeipc
timekernel
tsort
type
undefine
ved
vemacs
w
wc
wh
whi

References

^ ^a ^b "Past Research in the DSG". Distributed Systems Group. 20 July 1995. Archived from the original on 27 July 2012. Retrieved 14 September 2020.
^ Cheriton, David R. (1982). The Thoth system: multi-process structuring and portability. North-Holland. ISBN 0-444-00701-6.
^ Cheriton, David R. (January 1981). "The design of a distributed kernel". Proceedings of the ACM '81 conference on - ACM 81. pp. 46–52. doi:10.1145/800175.809831. ISBN 0-89791-049-4. S2CID 14212831.
^ Cheriton, David R. (March 1988). "The V Distributed System" (PDF). Communications of the ACM. 31 (3): 314–333. doi:10.1145/42392.42400. S2CID 7523994. Archived from the original (PDF) on August 12, 2017. Retrieved June 25, 2011. Reprinted in Innovations in Internetworking ISBN 0-89006-337-0
^ Cheriton, David R. (February 1988). "Versatile Message Transaction Protocol". RFC 1045. doi:10.17487/RFC1045. Retrieved June 25, 2011.
^ Cheriton, David R. (1986). "VMTP: A transport protocol for the next generation of communication systems". ACM SIGCOMM Computer Communication Review. 16 (3): 406–415. doi:10.1145/1013812.18217. ISBN 0-89791-201-2.
^ Deering, Steve (August 1989). "Host Extensions for IP Multicasting". RFC 1112. doi:10.17487/RFC1112. Retrieved September 4, 2013.
^ Nowicki, William I. (March 1985). Partitioning of Function in a Distributed Graphics System (PDF). Stanford University. Technical Report CSL-85-282
^ Hahn, Harley (1995). The Unix Companion. Osborne McGraw-Hill. p. 45. ISBN 0-07-882149-5.
^ Finlayson, Ross S.; Hennecke, Mark D.; Goldberg, Steven L. (1993). "From V to Vanguard: the evolution of a distributed, object-oriented microkernel interface". USENIX Symposium on Microkernels and Other Kernel Architectures: 3.
^ Meer, Veigh S. (January 1985). "After Newcastle, What? A Report on the Distributed UNIX Meeting" (PDF). Australian Unix Users Group Newsletter. Vol. 5, no. 6. Australian Unix Users Group. pp. 5–9.
^ V-System 6.0 Reference Manual