From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="iso-8859-1" From: Borja Marcos To: 9fans@cse.psu.edu Subject: Re: [9fans] What makes Plan 9 unique? References: <9r783d$s5l$1@newpoisson.nosc.mil> In-Reply-To: <9r783d$s5l$1@newpoisson.nosc.mil> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-ID: <100411057301@192.148.167.16> Date: Fri, 26 Oct 2001 17:36:11 +0200 Topicbox-Message-UUID: 0e9edeb0-eaca-11e9-9e20-41e7f4b1d025 On Thursday 25 October 2001 11:00, you wrote: > What makes Plan 9 truly unique? What about it makes it better than > Solaris, or other UNIX systems? =09I don't think Plan 9 can or should be compared to Unix systems. Plan 9= is=20 a distributed system, and Unix is not. =09One of the things that impressed me the most the first time I read a=20 description (some years ago, long before AT&T decided to sell research=20 licenses), was its capability to work in *heterogeneous* networks. It is perhaps the most significant feature in Plan 9. =09Another distributed operating system, Amoeba, converts a whole network= =20 into a sort of huge multiprocessor computer (from the user's point of=20 view), but it does not take into account the differences between networks= ,=20 so Amoeba may be good for organizations with a high speed local network. =09Plan 9 does not have automatic process migration like Amoeba, but, for= =20 the designer of a distributed application, Plan 9 offers the ability to=20 decide how to use the network depending on the available resources. The=20 figure 1 in the original Plan 9 paper shows an example; CPU and file=20 servers linked by a high-speed optic network, and remote terminals workin= g=20 from a phone line. The speeds can range from a 9600 bps line to a gigabit= =20 network. =09Plan 9 offers a per-process namespace that can be configured to make t= he=20 network topology completely invisible to the user or the application=20 program. Moreover, it has taken the "everything is a file" idea to the=20 extreme. The network services, for example, are seen as files. To open a=20 connection you only copy one "master" file, and the new file obtained wil= l=20 be the new connection. =09Together with this, Plan 9 offers a very clean network filesystem. It = can=20 export *anything*. One of my favourite examples is a machine "mounting"=20 the TCP/IP stack of another through a network, or a process in one machin= e=20 being debugged by a debugger in another. Classic network filesystems don'= t=20 allow this flexibility. =09The window system makes a heavy use of the "everything is a file" noti= on,=20 and it is extremely flexible and simple. It does not have a specialized=20 protocol for network operations such as X11. Offering a file interface, i= t=20 uses 9P. In fact, as the screen itself is a file, you can run one window=20 system inside a window. =09This is what I liked most about Plan 9. There are obviously more thing= s.=20 The user interface is not the typical interface you see in the rest of=20 environments, it shows new ideas.=20 =09I even love the documentation; a set of two books in the old Unix=20 fashion. A set of very well written papers describing the different=20 components and tools, and the manpages. =09Summarizing, in a time when you don't see anything new from commercial= =20 operating system vendors, and when everything is either Unix (note that I= =20 am a heavy FreeBSD user) or (argghhh) Windows, an operating system with a= =20 truly innovative design is fresh air ;-) =09Borja.