Maximum Security:
A Hacker's Guide to Protecting Your Internet Site and Network
  
21
Plan 9 from Bell Labs
Almost thirty years ago, the team at Bell Labs (now Lucent Technologies) changed
the world by developing what would later become the most popular networked operating
system in history. From then until now, UNIX has ruled the Internet. Even if that
were the only contribution ever made by Bell Labs personnel, it would have been sufficient.
They would been have been held in high regard as having achieved something truly
useful and important. As any programmer will tell you, however, the contributions
from Bell Labs kept coming.
In the early 1990s, the folks at Bell Labs were still busy. This time, however,
they had more than 25 years of experience under their belts. With that experience,
they challenged themselves to create the ultimate networked operating system.
Did they succeed? You bet. It is called Plan 9 from Bell Labs.
The Basics
The team at Bell Labs (which includes such heavy-duty names as Ken Thompson and
Dennis Ritchie) were reportedly dissatisfied with the then-current trends in computer
technology. They realized that hardware considerations made networking a difficult
proposition, one that didn't always work out in terms of cost effectiveness or performance.
Hardware dependencies and proprietary design make networking more of a forced environment
than a truly fluid, easy one. By forced environment, I mean that dozens of
often disparate and incompatible protocols, drivers, and software are patched together
to provide a shaky and sometimes unreliable integration of networks.
Alas, although the Internet may sometimes be referred to as a miracle of distributed
computing, it isn't. The current system works only because we have forced the TCP/IP
stack upon a handful of architectures (many that were never designed to run these
protocols). Thus, the Internet has the appearance of being an amalgamated,
united network. On closer examination, however, it is clear that the Internet is
exploiting only a very meager portion of the networking power at its disposal.
Consider this: FTP is one of the most commonly used techniques to move information
from one place to another. When a user transfers a file via FTP, he is a remote
user, accessing some resource on a server in the void. The word remote is
the key feature here. It denotes a condition wherein the user is isolated. To access
the resources at the other end, the user must perform several actions (these may
include initiating the FTP session, unzipping the file, placing it in the proper
directory, and so on). FTP therefore places the user at arm's length. The use of
the resource does not occur in a fluid environment.
Similarly, and to an even greater extent, HTTP isolates the user. True, it appears
to the user as though he is working interactively with a Web site, but he isn't.
In fact, HTTP may isolate the user more than any other network protocol. For example,
you are not logged in as you are with Telnet or FTP. In fact, you are connected only
for the brief periods--seconds, actually--necessary for your client to relate which
resources it needs. This is the farthest thing from a traditional shared network
environment.
In contrast, suppose that instead of retrieving a file and placing it in your
physical location, you simply want to use the file momentarily. This is sometimes
achieved through file sharing in proprietary network environments (environments where
a directory or a file can be attached to the local machine). In such cases, the resource
appears and behaves as though it is on the local machine. This technique is more
akin to true, networked computing. It is a one-step process.
Now imagine an operating system that was designed to interface in this manner
with many different types of systems and hardware, an operating system that could
provide this real networking to hundreds (or even thousands) of workstations, irrespective
of hardware constraints. Imagine an operating system that makes FTP directories of
remote machines appear as local directories (regardless of where the target server
may be located). If you can imagine this, you are well on your way to understanding
the basic characteristics of Plan 9.
What Plan 9 Is Not
Plan 9 is not UNIX, or any variant thereof. But if you install the demo distribution,
you may initially be confused on this point. At first glance, it looks a lot like
UNIX (particularly when you make a directory listing). Make no mistake, though. Plan
9 is an entirely new operating system. As explained in the Plan 9 from AT&T Bell
Laboratories FAQ:
- Plan 9 is itself an operating system; it doesn't run as an application under
another system. It was written from the ground up and doesn't include other people's
code. Although the OS's interface to applications is strongly influenced by the approach
of UNIX, it's not a replacement for UNIX; it is a new design.
NOTE: Visit the Plan 9 FAQ http://www.ecf.toronto.edu/plan9/plan9faq.html.
Despite the fact that Plan 9 is an entirely different operating system, it does
retain some of the look and feel of UNIX. There is still a shell (called rc)
and that shell appears much like the popular shells available in most distributions
of UNIX. Files, for example, can still be displayed in a UNIX-like long format, along
with their attending permissions. Moreover, one can still differentiate between files
and directories using the standard -F switch (in fact, many of the stock
UNIX commands are available and most of these behave pretty much as they do on a
UNIX box). However, the resemblance to UNIX is largely superficial. The underlying
operating system works very differently.
One of the chief differences is the way that Plan 9 treats objects (objects in
this case being directories, files, processes, and so forth). Under Plan 9, all objects
are treated as files. This technique has been implemented in UNIX as well (for example,
UNIX treats many devices as files), but not to the extent that it has in Plan 9.
Machines That Run Plan 9
The reported architectures include
- MIPS
- SPARC
- 68020 (NeXT)
- IBM compatibles
It is reported in the Plan 9 from AT&T Bell Laboratories FAQ that various
ports are also underway for the following systems:
- SGI Indy
- DEC Alpha
- PowerPC
- DECstation 2100 and 3100
My experience with installing the Plan 9 distribution has been on the IBM compatible
platform. As you will see, I went through several generations of hardware before
landing on the right combination.
Cross Reference: If you intend to install
Plan 9 as a hacking project, you would do well to visit http://www.ecf.toronto.edu/plan9/clone.html.
This page describes the hardware that was used at Bell Labs, and will provide you
with a nice guideline of hardware that is known to work with Plan 9.
Some Concepts
Plan 9 was designed from the beginning as a networked operating system. As such,
the concepts behind it relate more to networking than to the needs of the individual
user. Its defining characteristics are the ways in which it handles networking. As
noted in the press release for the product:
- The Plan 9 system is based on the concept of distributed computing in a networked,
client-server environment. The set of resources available to applications is transparently
made accessible everywhere in the distributed system, so that it is irrelevant where
the applications are actually running.
Cross Reference: Find the press release
from which the preceding paragraph is excerpted at http://www.lucent.com/press/0795/950718.bla.html.
To understand how the Plan 9 system differs from other networked operating systems,
examine Figure 21.1.
FIGURE 21.1.
The typical network configuration (without Plan 9).
The typical network configuration (the one most often seen in offices) uses a
file server and a series of workstations. Each of the workstations is outfitted with
a host of hardware and software (hard disk drives, adequate memory, a windowing system,
and so forth) that provides it with the necessary power and networking to connect.
System administrators and other, administrative personnel will recognize this setup
to be an expensive one.
Because the computer industry has enjoyed tremendous growth (particularly in the
last few years), network designs like the one shown in Figure 21.1 are common. Nodes
on such networks are usually Pentiums or PowerPCs. You may own such a network yourself.
If you do, consider this: Is it necessary that you have such a powerful machine at
each node? Or, could it be that this type of configuration is a profligate waste
of enormous CPU power? For example, how much CPU power does the accounting department
actually require? It depends on what operating system you are running. If you are
running DOS-based applications over NetWare, the accounting department doesn't need
much power at all. However, if you are running Windows 95, it will need speed and
memory.
That speed and memory, by the way, is being eaten purely by features that make
your platform prettier and more user friendly. In practice, the average accounting
task done in a DOS-based application would be barely noticeable to a Pentium processor.
Contrast that with accounting done in Microsoft Excel on the Windows 95 platform.
In reality, processor-intensive tasks requiring real power might include tasks like
compiling large programs in C++. These tasks, even in a DOS environment, can tax
a processor.
So the first point is this: Modern network design wastes processor power by dispersing
it, often where it is not most needed. But there are other key disadvantages to this
typical network implementation. One is that files are strewn throughout the network,
many of them deposited on this or that hard disk drive. How many times have you encountered
the following situation:
- 1. A machine along the network fails.
2. The machine that failed has a file vital to office operations.
3. You recover that file (usually by depositing the hard disk drive from the
failed machine into another, operable one, or by performing a restore).
If you have never encountered this situation, consider yourself lucky. I have
seen it happen many times. Also, because users often store files locally (on their
own workstation), employees must file share and therefore, their machines must always
trust each other.
Plan 9 takes a totally different approach. In Plan 9, the jobs of processing and
file storage and separated, as are the machines that perform these tasks (see Figure
21.2).
FIGURE 21.2.
The Plan 9 networking concept.
Note the CPU server in Figure 21.2. This would typically be a very powerful machine
(probably multiprocessor) that would provide CPU services to remote workstations
or terminals. This is complemented by a file server.
This system has some important advantages. First, there is centralized control
of files. This has obvious security advantages. Centralized file control also allows
easier management of files. Moreover, it provides an environment in which permissions
may be easily viewed and alteration of files may be more readily detected.
Also (though this has little to do with security), as mentioned in the Plan 9
documentation, this centralized file management is of benefit to a programming team.
Project management is more easily accomplished and the system offers a sense of community
for the programming team.
Moreover, the Plan 9 system performs without a root operator. Users must be authenticated
to gain access to privileged files or processes, and this authentication has been
described as similar to authentication using MIT's Kerberos. Kerberos is a method
of authenticating network connections and requests. To perform this authentication,
Kerberos examines secret, ciphered keys belonging to the user. Passwords in Plan
9 are therefore never passed across the network. This greatly enhances the security
of the operating system. Moreover, user programs are reportedly never run as processes
on the file server, and processes that are run belong to the individual user. Root
does not exist.
Cross Reference: To examine the internal
workings of Kerberos (and the procedural execution of authentication), visit http://www.pdc.kth.se/kth-krb/doc/kth-krb_2.html.
Discarding the concept of root was an excellent idea. The majority of serious
cracking techniques rely on exploiting programming weaknesses in processes that run
as root. In Plan 9, there is no root, and therefore, no such processes.
NOTE: To my knowledge, there has not yet
been extensive focus on Plan 9 security outside the confines of Lucent Technologies
(previously AT&T). Therefore, it is not known whether there are security flaws
inherent in Plan 9's design. The only thing that qualifies as a known bug at this
point (those who use it have thus far been pretty quiet) is that users can sometimes
log in as user none from a remote connection. I suspect that in the future,
as Plan 9 becomes more well known, various attacks will be instituted against the
system and bugs will likely surface.
In short, Plan 9 security is an area yet to be explored. Nonetheless, in terms
of its network implementation and its basic design, Plan 9 already presents significant
roadblocks to the cracker. Certainly, typical advanced techniques of attacking UNIX
servers will probably fail when implemented against Plan 9. The future, however,
remains to be seen.
NOTE: I cannot stress the importance of
the concept of life without root. Nearly all operating systems evaluated as secure
maintain some concept of a root operator. The concept of root concentrates all the
power in a single place on the system. If a cracker can gain root, the struggle of
penetrating security is over. However, I should quickly point out that the absence
of root on a Plan 9 system does not mean that an administrator is not needed. In
fact, in certain respects, Plan 9 transforms the job of system administrator into
one of architect. In short, Plan 9 is designed for vast--if not massive--management
of network resources. Although still in the experimental stages, Plan 9 could change
the architecture of the Internet and with it, the concepts surrounding acceptable
security policies and implementations.
Applications Available for Plan 9
Admittedly, there are few native Plan 9 applications, but the list is growing.
Remember: Plan 9 is an entirely new operating system, so the number of applications
depends on how many individuals actually use the system.
NOTE: A caveat: The licensing restrictions
set forth by Bell Labs makes it very difficult to create commercial applications
for Plan 9. The licensing scheme has cast Plan 9 into a position of being available
only from Bell Labs at a high price and without hope in the near future of complete
commercialization. For now, therefore, Plan 9 remains largely under the purview of
researchers and hobbyists who are willing to shell out $300 for the system and documentation.
Many freelance programmers protest this situation, arguing that Plan 9 ought to have
licensing restrictions similar to those that apply to Linux. After all, why would
someone develop on a platform that may ultimately be barred from commercialization?
The answer is this: People would undertake such development for the pure pleasure
of discovering and hacking a new system. However, many hobbyists are unwilling to
pay the stiff licensing fee for the entire system.
Despite some licensing restrictions with Plan 9, some important applications have
already been written:
- An HTTPD server
- Text editors
- A version of MIT's X Window system
Moreover, the basic distribution of Plan 9 comes with a wide range of utilities
and even a native Web browser called Mothra. Mothra may not be as colorful
and user friendly as Netscape Navigator or Microsoft Internet Explorer, but it works
quickly and efficiently. In fact, Plan 9 possesses few user-friendly features. It
is a largely text-based environment. It is more practical than attractive, and many
elements of its design are of significant interest to programmers.
SAM
The most prominent native application for Plan 9 is the SAM editor, which is a
straight ASCII text editor with a twist. It has a command language that can be used
to process repetitive tasks (much like a macro language, I suppose, but a bit more
defined). On the surface, SAM operates in much the same way UNIX-based text editors.
File names (single or multiple) can be specified on the command line. This loads
the file(s) into a windowed area. There, the text can be clipped, pasted, cut, altered,
edited, and saved.
Like most UNIX-based text editors, SAM does not support multiple fonts, style
sheets, or other amenities common to modern word-processing environments. In fact,
Plan 9 would be a poor choice for anyone who relies on such amenities, for they do
not exist within the system at this time.
The SAM command language operates mainly on regular expressions and is suitable
for inserting, deleting, finding, replacing, and so on. These functions are generally
called by a single character, followed by your intended text. In other words, the
text to be found, replaced and so forth.
In short, SAM appears very bare bones, but really isn't. Learning the SAM command
language takes a day or so, although you might need several weeks to become proficient.
Plan 9's Window System
Plan 9 has a window system called 8 1/2.
After the system boots, it asks whether you want to load the window system. If you
choose this option, 8 1/2
appears. On first examination, 8 1/2
looks extremely rudimentary (far more so than X, even). The opening screen presents
one term window and a clock. Navigation is done largely with the mouse.
TIP: To fully utilize the 8
1/2 windowing system, you need a three-button
mouse. A two-button mouse will work, but you will lack at least one menu and some
serious functionality.
To size a window, click any portion of the blank screen. This invokes a
menu with options including Size, Move, Delete, and Hide. After you choose an option,
click the target window. For both the hide and delete functions, the window behaves
as it would in X; it disappears or is deleted. However, for the move and size functions,
you must work a little differently. After choosing the menu option, click the window
once. Then, instead of directly sizing or moving the window, click the black screen
again (this time with the right mouse button) and redraw your window. This may initially
seem awkward, but you'll get used to it.
8 1/2 is extremely lightweight.
Even on a machine with 8MB of RAM, 8 1/2
responds quickly. On a Pentium 133 with 64MB of RAM, 81/2 is incredibly
fast.
8 1/2 is more dynamic than
most other windowing systems. You can grab any text anywhere and use it as a command.
In this regard, 8 1/2 could
be called the ultimate cut-and-paste system. Text identifying objects (which is often
read only on other platforms) can be grabbed at any point and dropped into any other
part of 8 1/2. In fact, this
feature is so prominent that new users may find themselves grabbing things without
even knowing it. In addition, as part of this functionality, the cursor can be placed
anywhere within a window. This is a significant change. Users of X and Microsoft
Windows alike will find this feature to be fascinating. For example, although you
can cut and paste from an XTERM or a MS-DOS windowed prompt, you cannot arbitrarily
drop the cursor in any area and pick up typing again. In 8 1/2, you can.
I suppose 8 1/2 can best
be described as a window system optimized for programmers. Code and other data can
be moved at any time from any position. But perhaps the most fascinating thing about
8 1/2 is that you can recursively
run an instance of 8 1/2 within
an 8 1/2 window. To my knowledge,
this functionality is indigenous only to 8 1/2. No other windowing system can perform such a task. (Funny. Although
this is an extraordinary feature, I have not yet encountered a reason to use it.)
The learning curve on 8 1/2
amounts to a day or two at most. If you are familiar with any implementation of X
(or more directly, if you have ever used SunView), learning 8
1/2 will be simple. To some extent, 8
1/2 reminds me of SunView.
NOTE: SunView, a windowing system introduced
in early versions of SunOS (the operating system created by Sun Microsystems), is
extremely lightweight and, even on SunOS 4.1.3, is faster than Sun's later windowing
system, OpenWindows. OpenWindows is enormously popular among Sun users, although
it is perhaps slower--and not as visually stunning--as the Common Desktop Environment
(CDE), a new windowing system jointly developed by many UNIX vendors.
Programming in Plan 9
Ultimately, I would recommend Plan 9. If you are a programmer and are looking
for a new and exciting operating system to develop on, Plan 9 is for you. It is exciting
primarily because of its unusual design. And, although it is not UNIX, it has enough
UNIXisms that UNIX users can hit the ground running. Moreover, the unique networking
capabilities of Plan 9 present new opportunities for programmers.
Programming in Plan 9 is not limited to C, though the real Plan 9 distribution
does come with a native C compiler. This C compiler is designed to accommodate code
for all the supported architectures, including (but probably not limited to)
- IBM (Intel X86)
- SPARC
- 68020
- MIPS
The compiler accepts straight ANSI C, but be forewarned: If you have avoided learning
some of the newer conventions, you may encounter difficulties. Rob Pike has written
a paper describing Plan 9 C compiler usage. I highly recommend reading that paper
in its entirety before attempting to code any serious application on the Plan 9 platform.
Cross Reference: Rob Pike's paper, titled
"How to Use the Plan 9 C Compiler," can be found online at http://kbs.cs.tu-berlin.de/~jutta/c/plan9c.html.
If you plan to concentrate on porting applications to or from Plan 9, check out
the ANSI-POSIX Environment (APE). The APE features a wide range of POSIX tools.
Cross Reference: An excellent technical
overview of APE written by Howard Trickey ("APE--The ANSI/POSIX Environment")
can be found online at http://plan9.bell-labs.com/plan9/doc/ape.html.
NOTE: POSIX stands for Portable Operating
System Interface, a standard that has been in the works for many years. This standard
is an effort on the part of developers to establish a unified UNIX. In other words,
if a program is fully POSIX compliant, it should run on any fully POSIX-compliant
platform, be it SunOS, Linux, AIX, HP-UX, or other versions of UNIX. For many years
(and even now) there have been both sharp and subtle differences between various
UNIX platforms that prevent easy porting of applications. The POSIX standard will
likely change that. To learn more about POSIX, visit http://csrc.ncsl.nist.gov/nistbul/csl91-10.txt.
Garden-variety throwaway programming can also be done in rc, the shell environment
of Plan 9.
The complete distribution of Plan 9 also comes with extensive libraries, including
one for the development of windowed applications intended to run within 8
1/2 (windows are actually referred to as panels).
Tom Duff has written quite a good paper on the development of panels in Plan 9. He
likens the panel library to the popular development packages Tcl and Tk. Linux users
will be familiar with Tcl and Tk. Both are languages (and development libraries)
for use in generating X Window System applications. One of the most popular features
about Tk is that you can build a windowed application using a language very similar
to a macro language. It is possible to quickly develop applications using these tools
because objects within the window environment are placed by the use of direct statements.
For example, the command within a Tk script to create a button is:
button .name_of_button <options>
pack .name_of_button <options>
Similarly, the development syntax for windowed applications intended for use in
Plan 9 is reduced to direct statements (although this is still done using basic C).
Cross Reference: If you are interested
in developing windowed applications in Plan 9, Tom Duff's paper, "A Quick Introduction
to the Panel Library," can be found online at ftp://plan9.bell-labs.com/plan9/doc/panel.html.
Another interesting aspect of Plan 9 is its inclusion of the Alef programming
language. Alef is a relatively new language. Unfortunately, a discussion about the
Alef language is beyond the scope of this book (that is a delicate way of saying
that I know too little about Alef to provide you with quality information).
Cross Reference: To find more information
about Alef, check out the language reference manual. It can be found online at http://plan9.bell-labs.com/plan9/doc/ref.html.
Another important resource (probably even more valuable than the language reference
manual, especially for the newcomer to Alef) is the Alef mailing list. It can be
viewed online at http://plan9.wtf.nyc.ny.us/1996/0001.html.
In all, Plan 9 is a very rich development environment. One thing that makes it
especially exciting is that the field is wide open. It is a whole new operating system
just waiting for new and useful applications to be written.
Installing the PC Distribution
You might want to try out a working demo of Plan 9; Bell Labs has generously provided
such a distribution free of charge on the Internet. However, before you install Plan
9, there are some things you should consider. One is whether you should even begin.
As with any new operating system, you should expect bad things to happen. These may
range from simple installation failures to data or disk corruption.
NOTE: If such events occur, it is most
likely because you are using unsupported hardware. When the right hardware is used,
Plan 9 works beautifully. Of course, not everyone has the money to go out and acquire
the exact hardware used at Bell Labs. If your cash is limited, expect a certain amount
of trouble along the way.
Moreover, you'll experience a high level of frustration. If you have ever installed
an operating system that is less than user friendly, you know the terrain. Cryptic
errors may appear, and you will undoubtedly be forced to hack here and there. These
obstacles will be particularly prominent if you are installing the four disk, free
PC distribution on dubious hardware.
The Machine Targeted for Installation
The machine that you use should be free and clear. That is, under no circumstances
should you install the Plan 9 distribution on a machine that you rely on to make
a living (even if you are installing Plan 9 on a separate disk). There have been
instances in which Plan 9 installations have permanently disabled the boot capabilities
of other operating systems or partitions. The only reason you should make such an
installation is if your job requires it (or if you are a programmer who loves adversity).
Otherwise, use that old DX66 you have lying around in the closet.
If you only have one machine and still want to experiment, get a rack-mount disk
changer. This device allows you to switch hard disk drives quickly and easily. It
works in exactly the same fashion as a slide-out car stereo. Your hard disk drive
is secured in an enclosure that slides into your PC tower. In this manner, you can
switch from your regular disk drive (containing the operating system you use for
work) to the Plan 9 drive.
NOTE: To my knowledge, there have been
no known instances of Plan 9 installations damaging hardware, so there is no reason
why you should fear temporarily switching disks.
The machine need not be particularly fast, though I would recommend 66mHz or better.
I have installed the distribution on a DX33mHz, a DX266mHz, a DX4120mHz, and a 133
Pentium. To be honest, I did not find an incredible increase in speed between the
120 and the 133, nor did I find the difference between the 66 and the 120 unbearable.
However, the DX33 was admittedly quite slow.
Memory is important. You will need at least 8MB. Some documents on the Internet
suggest that there are individuals running Plan 9 with 4MB of RAM, and I believe
it. However, of the seven times that I installed the PC distribution, I was twice
confronted with an Out of Physical Memory message. This was, as it happens,
a fatal error. Immediately following this message, the installation failed. On both
occasions, I was using only 8MB of RAM. On an identical machine, after installing
additional RAM, I managed to complete the installation successfully.
The Hard Disk Drive
What hard disk drive you use depends on what you are installing. If you are simply
installing the PC distribution, you can successfully use a 40MB hard disk drive.
However, if you intend to install the entire Plan 9 distribution from CD-ROM, you
need a hard disk drive equal to or greater than 540MB.
TIP: It has been reported in documentation
that a 500MB disk will suffice. As far as I can tell, this is not entirely accurate.
If you make a direct installation from the CD-ROM, you will require a 540MB disk
(or approximately 532MB). The only way to get around this is to first install the
basic four-disk PC distribution, and then more incisively install the remainder of
the distribution from CD-ROM. This eliminates many items that are intended for use
on other platforms. Be advised, however, that this is a more difficult path and may
result in problems getting your CD-ROM to catch. (Sometimes, the CD-ROM driver does
not properly initialize the CD-ROM drive.) It is a much better idea to make the full
install and later delete what you do not need.
I recommend a 540 or 600MB drive. I should state that my installations were performed
entirely with IDE drives and therefore, I cannot give background on SCSI-based installations.
I obtained suitable results with the following drives:
- MiniScribe 8051A (41MB) (Don't laugh. It worked flawlessly.)
- Conner CFS540A (EZD03) (540MB)
- Quantum Maverick ProDrive #MV54AO11 (514MB)
- Maxtor 7245AT (243MB)
The Installation Process
I will assume that you are installing the four-disk PC distribution. This set
of four diskette images is located online at ftp://plan9.bell-labs.com/plan9/pcdist/README.html.
Download these into a temporary directory on your current hard disk drive.
NOTE: The term diskette images
refers to four files located at the Plan 9 site. These files are exact copies of
four diskettes required to make an installation set for Plan 9. These files or images
must be downloaded to your local machine and written to floppy diskettes.
TIP: It is important that you obtain the
disks from this site. Earlier versions of these boot disks may be available at other
locations, but you should not use them. On installation, earlier versions have a
tendency to damage other partitions on the disk drive. A typical example would be
where Plan 9 disabled a Linux partition during the installation process. Again, I
strongly advise against installing Plan 9 on any hard disk drive that contains vital
or irreplaceable information.
The diskette images at that location are
- disk1
- disk2.vd
- disk3.vd
- disk4.vd
After you download these diskette images, write them directly to a floppy.
NOTE: Copying the diskette images to a
floppy involves a process that is different from copying files to a floppy. Copying
the diskette images directly to floppy will not suffice and will result in an installation
failure.
A number of utilities for writing disk images to floppy disks are available. The
most popular is a program called DD.EXE. A DOS version (suitable for use
under Windows 95) is available on-line at
Another utility used for this purpose (and one that is more widely available on
the Internet) is RAWRITE.EXE. Linux users will be familiar with RAWRITE.EXE
because it used to write the boot diskette images for Linux to a floppy. RAWRITE.EXE
is available online at
After you write these images to a floppy, switch to the target machine (or hard
disk drive). On the hard disk drive of the target disk, you must establish a DOS
partition. The size of this partition is not particularly important (I use 10MB).
It really only needs to be large enough to hold DOS and approximately 1.5MB of information
in a directory called C:PLAN9.
Partitioning the Disk
To partition the disk, use the FDISK.EXE utility (see Figure 21.3).
FIGURE 21.3.
The FDISK utility.
First, delete all partitions (you will be starting over with an entirely clean
disk). Allocate whatever space you intend for the DOS area (I recommend at least
11MB). After you reboot your machine, you will format this partition and install
DOS onto it.
NOTE: At this stage, you should have a
hard disk drive with one DOS partition at least 11MB in size. The rest of your hard
disk drive should not contain any other type of partition.
Installing the Basic Plan 9 System
The remaining steps of this portion of the installation are simple. Boot with
the Plan 9 boot diskette (this is the diskette to which you wrote the disk1
file). During the boot process, you will see a series of messages; most are easy
to read and interpret. Plan 9 tracks your memory and reports what portions of it
are available. It identifies your hardware. Ultimately, it brings you to a nice blue
screen, which contains the heading System Installation & Configuration.
From this screen, you perform the installation. Pressing the Enter key invokes
a menu containing various installation options. Ensure that these are correct for
your machine. When you are satisfied that these options are correct, choose the Install
option.
A window will appear, and many filenames will scroll past. Do not be alarmed.
This is Plan 9's way of telling you which files were installed. When this process
is complete, Plan 9 interrogates you about your hardware. Specifically, options must
be set for your VGA, mouse, and so forth. Provide the necessary answers and choose
Save Configuration from the menu.
NOTE: Plan 9 gives you an opportunity
to change the options before they are committed to the disk. A dialog box appears,
listing your options. If they are incorrect, go back and change them.
After the options have been saved, you can remove the floppy disk and reboot the
machine. Your DOS should boot normally. As mentioned previously, almost all problems
with this installation procedure occur at time of booting disk1. To my knowledge,
there have been few instances of problems occurring on the reboot to DOS.
Installing the Remaining Diskette Files
After you reboot your machine, change your current directory to C:PLAN9
and type the letter B to load an installation program. You must define the
target disk drive. This tells Plan 9 in which disk you intend to house the Plan 9
file system. I am assuming here that you have a single disk, so this is not an issue.
But if you are installing to a machine with multiple disks (and partitions), take
extra care to ensure that it is the correct partition.
WARNING: If you choose the incorrect partition,
all your data on that partition will be lost. Be absolutely certain
that you have chosen the correct partition before you commit to the install procedure.
After you choose your partition, Plan 9 begins the file system installation process.
A dialog box appears, prompting you to insert the second disk into the floppy disk
drive. After you do so, the installation of system files commences. You will again
see a pop-up window with filenames scrolling by. Insert disks as the program requests
them. When the installation procedure is complete, you will be prompted by a menu.
Choose the option that says Make the newly installed Plan 9 the default.
Congratulations. At this stage, the installation procedure has been completed.
You can now remove the fourth disk, reboot your machine (choose this menu option),
and begin to explore Plan 9.
Starting Plan 9
When you machine reboots, change your current directory to Plan 9. There, type
the command
B
This loads the Plan 9 system. First, you will see many of the same messages you
saw when you booted with the boot floppy (Disk1). The system will identify
your hardware, count your memory, and describe some resources. When it is finished,
a line that looks like the following will be printed to your terminal:
root is from (local, 9600, 19200, il)[local!#H/hd0fs]:
Press the Enter key. You will then be prompted with a line that looks like this:
user[none]:
Press the Enter key again. Depending on the speed of your system, you will soon
be asked whether Plan 9 should start the window system. Choose Yes.
If you have gotten this far, 81/2 should load cleanly (barring some
obscure error). If so, you will be presented with a bright screen (its color may
depend on your video card; on mine, the screen is white), a clock, and a window with
the contents of the README file printed within it. Welcome to Plan 9. (Look
at the size of that mouse cursor!)
Navigating the file system works much like it does in UNIX. You can use the CD
command to get from directory to directory. Here are some minor notes that may assist
you on your first test drive of Plan 9:
- The -a option in the ls utility is not supported. You are not
crazy, it is simply not available in Plan 9.
- The -F flag is supported in Plan 9. However, the output appears a bit
differently than in UNIX. The character that denotes a directory is found on the
extreme left of the table, not the right. It is easy to miss.
- If you are a big fan of the MORE utility, you may be disappointed. Use
CAT instead.
- If you want to get an overall look at the system, start ACME. This utility works
a similarly to a file manager, revealing files and directories. These can be opened
within the ACME environment.
- DF is not supported, but DU is.
Summary
Plan 9 from Bell Labs is a new and unique operating system that offers an entirely
new outlook on Internet security. Still, it is far from supplanting modern UNIX.
(In fact, many people believe that the next commercially viable operating system
will be Inferno from Lucent. To some extent, this is true, because Inferno is now
being used in set-top boxes for interactive TV.)
Plan 9 seems best suited for very large organizations. The system appears to have
been designed expressly with the Internet in mind and on a grand scale. I would call
it some finely crafted mortar with which to seal the cracks in modern networking
techniques. Because there is little research available on the security model of Plan
9, we must simply wait and see. However, as a hacking project, I cannot think of
a better start than Plan 9 from Bell Labs.
Resources
Following are several resources on Plan 9, including sites on the WWW, papers,
and mailing lists (of course, some may change by the time you read this book). It
seems that the Plan 9 computing base is a small (but growing) faction, making information
on this new operating system scarce.
Plan 9 on the WWW
The Plan 9 Server Document Directory
The Plan 9 PC Diskette Installation Distribution
The Plan 9 FAQ
Technical Documentation on Plan 9 (Papers)
Overview of the Plan 9 File System
The Plan 9 Mailing List Archive
Online Bibliography on Plan 9
The Plan 9 Usenet Newsgroup
The Unofficial Plan 9 Page (Very Good)
Plan 9 Web Server at the University of York (UK)
Official Plan 9 Home Page
Articles and Such
Plan 9: Son of UNIX. Robert Richardson. LAN Magazine (Volume 11,
Page 41). August 1, 1996.
Plan 9: Feature Film to Feature-Rich OS. Paul Fillinich. Byte Magazine
(Volume 21, Page 143). March 1, 1996.
Plan 9 from AT&T. David Bailey. UNIX Review (Volume 1,
Page 27). January 1, 1996.
Plan 9 from Bell Labs. Rob Pike, Dave Presotto, and Phil Winterbottom.
Computing Systems Journal (Volume 8, Page 221). Summer, 1995.
Plan 9. Sean Dorward, Rob Pike, and Dave Presotto. UNIX Review (Volume
10, Page 28). April 1, 1992.
Designing Plan 9. Rob Pike, Dave Presotto, and Ken Thompson. Dr. Dobb's
Journal (Volume 16, Page 49). January 1, 1991.
Is Plan 9 Sci-Fi or UNIX for the Future? Anke Goos. UNIX World (Volume
7, Page 61). October 1, 1990.
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