Category : Alternate Operating Systems - Quarterdeck DesqView, CP/M, etc
Archive   : PCCDOC.ZIP
Filename : PCCDOC

Instructions for using PC-Choices

(Version 0.5c, ftp distribution, 27 Apr 92)

This document explains how to install and run PC-Choices. If you
encounter any problems, please contact Lup at [email protected].

What is PC-Choices

PC-Choices is a version of Choices for 386/486 PCs. Choices is a
portable object-oriented operating system developed by the University
of Illinois' Systems Research Group, headed by Prof. Roy Campbell.
The PC-Choices kernel runs in 32-bit protected mode and calls
DOS/BIOS in 16-bit virtual-8086 mode for input/output operations.
Because it uses DOS/BIOS instead of working with I/O hardware
directly, PC-Choices will run on many PCs. PC-Choices is written
mainly in C++ and the source code is available free-of-charge to
people who sign the educational/research license. PC-Choices contains
no proprietary code.

System requirements

A 386/486 PC running DOS version 3.0 or higher; EGA or VGA display;
at least 3 Meg extended memory. PC-Choices does not swap out memory
so it may not run properly without lots of extended memory (say 5 Meg).
3 Meg of disk space is required for storing the Choices kernel and
application files.

What does it do

PC-Choices runs 32-bit Choices applications and supports multitasking.
The PC-Choices package has a command shell, some file utilities,
a kernel browsing tool, a kernel visualization monitor and some
simple applications. Users can compile PC-Choices applications
with DJGPP, the DOS port of g++. Applications are written using
the Choices object-oriented application programming interface.

Who should use PC-Choices

People interested in object-oriented operating systems; people
who want to build 32-bit applications and run them in a multitasking
PC environment; people who want to learn how protected-mode PC
operating systems can be implemented in C++. PC-Choices is
currently available for beta-testing. PC-Choices has been tested
on the IBM PS/2 Model 80, IBM PS/2 Model L40SX, IBM PS/55 Note,
ALR Business VEISA 486-33, AT&T 6386WGS and other 386 PCs, with
DOS 3.3, 4.0 and 5.0.

_____________________________________________________________________________
PC-Choices Incompatibilities

(1) All extended memory must be usable by PC-Choices. PC-Choices will
not work if there are programs or data in extended memory. Some
DOSs make use of extended memory and are therefore incompatible
with PC-Choices. Change your system configuration before running
PC-Choices so that nothing is loaded into extended memory.
Here are some tips for DOS 5.0 users: don't use "DOS=HIGH",
DEVICEHIGH, HIMEM.SYS or SMARTDRV.SYS in your CONFIG.SYS and
AUTOEXEC.BAT files.

(2) The machine should not be in virtual-8086 mode when starting
PC-Choices. Some memory managers such as EMM386.SYS put the
machine into virtual-8086 mode while running. Remove these
memory managers from your system configuration.

(3) PC-Choices assumes that there is 640K of base memory, and uses
300K of low memory by default. The amount of memory to be used
may be adjusted by changing the configuration file pcc/bin/config.

(4) PC-Choices always uses the first text-mode display page for console
output.

Warning: It is possible that PC-Choices will damage the data on your
diskette or hard disk (although this has never happened
before). Make sure you have backups of your disks before
running PC-Choices.

_____________________________________________________________________________
Setting up PC-Choices

To fetch the PC-Choices package, ftp anonymously to choices.cs.uiuc.edu.
Get the file Choices/PC-Choices/pcc.zip in binary mode. (This document
you're reading is in the file Choices/PC-Choices/pccdoc.) Copy pcc.zip
to the PC, say to the root directory on the C drive (c:\). You should
have an UNZIP utility that unpacks ZIP archives. (Contact
[email protected] if you don't.) Unpack pcc.zip with your UNZIP utility
like this:

unzip -d pcc.zip

(Note: Some old versions of PKUNZIP are buggy and will complain about
about CRC errors when there are really none. Use the newest version of
PKUNZIP or use Info-ZIP's UNZIP instead.)

The directories pcc, pcc\bin and pcc\cbin and their files will be
unpacked in the current directory. Delete pcc.zip. (If a previous
version of PC-Choices is already installed on your machine, UNZIP
will ask you whether it should overwrite the files; just say "yes".)

We now have to edit pcc\bin\profile to tell the command shell
(Chocs) where to look for the Choices application binaries. Edit
pcc\bin\profile and you will see this:

PATH=d:/pcc/cbin

Change it so that it references the correct directory. For example,
if you unpacked the PC-Choices package in c:\, you should change
the line above to:

PATH=c:/pcc/cbin

If your PC is an IBM PS/2, PS/55 or something similar, edit
c:\pcc\bin\config, change "PS2Keyboard = no" to "PS2Keyboard = yes",
and change "PS2Timer = no" to "PS2Timer = yes".

PC-Choices is now ready to be used.

_____________________________________________________________________________
Booting PC-Choices

Go to the pcc\bin directory and type "pcc". After a while, you
should see

Choices Command Shell (Chocs 0.0)
For help contact [email protected]

Choices>

If the system does not respond to any keypresses, you cannot continue
using PC-Choices. You should reboot the PC, change the system
configuration and boot PC-Choices again. Look at pcc\bin\config to
find out what parameters you can set in order to make PC-Choices
run on your system.

If you still have difficulty running PC-Choices, please contact
me as soon as possible - I'm very eager to fix all compatibility
problems.

_____________________________________________________________________________
Running Applications

The "Choices>" prompt indicates that you're in the Choices command
shell, which allows you to run applications. For more information
about the shell, enter "help". Here is an incomplete list of
applications that are available (see pcc\cbin\readme for the complete
list):

ls - List the contents of the current directory.
cd - Change current directory. Without arguments, it prints the
name of the current directory.
hello - Prints a message. Can be used with an argument.
flash - Flash the screen 5 times.
count - Display digits 9 to 0 in large print.
worms - Draw a worm on the screen.
logo - Displays the PC-Choices logo.
kindred - "kindred X" shows all living objects in the kernel that belong to
class X and its subclasses. (Try "kindred Process",
"kindred MemoryObject" and "kindred Domain".)
dos - Start a DOS shell as a PC-Choices process.

To execute an application, just enter its name and arguments at the
shell prompt; the shell works like the Bourne shell. To execute an
application in the background, type the application name and arguments,
and type '&' at the end of the line before pressing Return.

If you see the message "Store::alloc() out of memory" while
multitasking, it means that the PC does not have enough memory to run
multiple programs at the same time. You can still use PC-Choices by
running a single program at a time.

To shut down PC-Choices, enter "exit" at the shell prompt and the machine
will return to DOS.

_____________________________________________________________________________
Kernel Visualization Monitor

PC-Choices can visualize its kernel state. Enter "monitor".
You should see 10 stripes (called "sliders") at the bottom on the
screen. A slider moves when the labelled event happens. The
sliders keep track of these events:

DOS: Calls to DOS functions (INT 0x21).
Disk BIOS: Calls to BIOS disk functions (INT 0x13).
Keyboard BIOS: Calls to BIOS keyboard functions (INT 0x16).
Interrupt: Hardware interrupt passed to BIOS.
Context Switch: Switching the contexts of processes.
CPU Idle: CPU is currently idle.
Process N: Application process N is currently running.

Try running various applications in the foreground and background
and see how the sliders behave. To turn off the sliders, enter
"monitor" again.

_____________________________________________________________________________
Questionnaire

The PC-Choices project team would like to obtain your comments
in order to make PC-Choices more useful for you. Please answer
the following questions (all answers are optional):

Please write down your occupation and describe your interests.

A--->

Would you like to use PC-Choices in your work? As a hobby?
How would you use it?

B--->

What new applications would you like us to develop?

C--->

If you could use the PC-Choices application compilation
environment, what applications would you write?

D--->

Do you want the source code for the PC-Choices kernel? Do you
want the ability to customize the kernel by recompiling the
kernel yourself?

E--->

How do you feel about the performance of PC-Choices? Is disk
I/O too slow for ordinary use?

F--->

Have you heard of the Choices project before? How much do you
know about it?

G--->

Other comments:

H--->

Please return the questionnaire to [email protected]. Thank you.

_____________________________________________________________________________
Overview of Choices

Choices, the object-oriented operating system, is well-documented;
many papers have been written about it. It is an operating system
composed of C++ objects. When Choices is running, numerous
objects work together in the system in order to provide operating
system services. Examples of Choices objects are Processes, Domains,
MemoryObjects, CPUs, Semaphores and NameServers. A Domain is a virtual
memory space in which Processes run, and MemoryObjects represent data
regions in the Domain that are accessible to Processes. In Choices,
C++ classes are also objects, so that programs may ask an object to
return its class, and given a class, find out all the superclasses
and subclasses of the class. Programs may also find out all instances
of the class.

Many modern operating systems operating-systems are object-based,
but only Choices is a real object-oriented operating system, because
it uses class hierarchies. For example, SystemProcess is a subclass
of Process. ApplicationProcess is also a subclass of Process. A
SystemProcess is a special kind of Process that executes in supervisor
mode and is non-preemptable. An ApplicationProcess is a special
kind of Process that executes in user mode, and is preemptable.
Both SystemProcess and ApplicationProcess inherit methods from Process,
but because they have different characteristics, the two subclasses
define certain methods differently. MemoryObject is subclassed
to represent various types of data stores such as physical memory
ranges, files and disks.

Subclassing is also used to make the operating system as modular
as possible, and to encapsulate machine-dependent characteristics
in separate subclasses. For example, CPU has subclasses i386CPU,
NS32332CPU, MC68030CPU and SPARCCPU, all of which define their
methods differently to handle CPU-specific operations like
context-switching and exception-handling.

Choices application programs are written in C++ in an object-
oriented manner too. System calls in Unix and most other operating
systems are flat function calls. System calls in Choices are object-
oriented - the kernel gives an application program pointers to kernel
objects and the program may invoke methods on these kernel objects to
perform system functions. In the object-oriented interface,
applications may create kernel objects such as Processes, Semaphores,
Domains and MemoryObjects. Kernel objects are not literally handed
to the application program; Choices contains a secure kernel
interface whereby "proxies" representing kernel objects are actually
handed to the application program, and calling any method on that
proxy will cause a trap into the kernel, and after checking the method
arguments, the method call will be forwarded to the appropriate kernel
object.

Choices has been ported to the multiprocessor Encore Multimax,
AT&T 6386WGS, IBM PS/2, Apple Macintosh IIx, SPARCstation I & II,
and we are currently porting it to the Intel Hypercube iPSC/2 and
Silicon Graphics workstations. The Multimax port of Choices currently
has the most number of Choices applications. Many Unix applications
have been ported to Multimax Choices: g++, gas, bash, GNU file
utilities and GNU Smalltalk. Multimax Choices runs TCP/IP and
provides Telnet and FTP services.

PC-Choices is a new port of Choices to 386-based PCs running DOS.
This is an interesting project because this is the first time
that a minimal Choices kernel has been isolated. The PC-Choices
kernel is only concerned with process management, virtual memory
and interrupt handling. All other services are provided by DOS
and BIOS, which run as user processes. Application libraries are
provided to map the DOS and BIOS interface into an object-oriented
interface so that Choices applications built for other ports
of Choices will run easily under PC-Choices. Applications may call
DOS and BIOS routines through a special object-based interface, and
through this interface, applications may also spawn off DOS processes.

PC-Choices was compiled on a SPARCstation with a g++ cross-compiler
for fast compilation. The PC-Choices application libraries and
system interface header files have been ported to DOS, and PC-Choices
applications may be produced by simply compiling them with DOS g++
(DJGPP) and linking the object files with the PC-Choices libraries.

There is currently a small group of Choices researchers. These people
are involved in many diverse research projects, such as distributed
virtual memory, message-passing, transaction processing, networked
filesystems, networking protocols, Unix compatibility, performance
visualization and object-oriented graphical interfaces.

_____________________________________________________________________________
Conclusion

If PC-Choices ran on your PC without major problems, you might want
to try out the PC-Choices application development package,
which lets you compile PC-Choices applications under DOS. DOS g++
(DJGPP) is required for compiling the applications. Contact
[email protected] for information on obtaining the application
development package.

Thank you for using PC-Choices.

Lee Lup Yuen
[email protected] Graduate Student PC-Choices Manager