by

Goals of Operating Systems

Primary goal:

- make it convenient for user to interact with the machine

Secondary goals:

- execute programs

- use hardware efficiently

What is an Operating System and What Does it do?

- Install & Run programs

- Copy, edit, delete, files

- Access peripherals like printers, modems, sound cards, scanners etc.

Types of Operating Systems

Computer Processor Architectures and Operating Systems

MS-DOS (MAC - AppleDOS AKA ProDOS), OS/2 Warp, VMS, THEOS, GNEISS.

OS can only run one program at a time

Ex. MS-DOS.

OS can run several programs at once

Ex: Win 95, Linux.

1. Quick View Plus 5.1

2. Windows 98 Second Edition Upgrade

3. Microsoft Plus! 98

4. Windows 98 2nd Edition

5. ClockWatch Pro

6. Complete Linux Operating System 6.0

7. Official Red Hat Linux 6.1 Deluxe

8. Windows NT Workstation 4.0

9. FreeMem Pro

10. DAVE 2.1

Introduction
In 1998, the press discovered Linux. Soon after, big business discovered Linux. Both generally agree that Linux is an excellent operating system which has the potential to topple Microsoft. Ironically, Microsoft themselves are praising Linux, to save themselves from anti-monopoly action.

At first glance, Linux looks much like just another Unix, hardly cause for such excitement. Why is Linux so popular?

Features
Linux is very, very stable. It almost never crashes. Linux systems can go for months or years without rebooting, which is very important for servers. Networking features and software are excellent. Linux will run on almost any modern computer, with wide hardware support. Linux has efficient multitasking and memory handling. It offers a secure multi-user environment. It is also free, not just by being available at little or no cost, but also because it is not owned by any individual or organisation.

Linux still relies on text file based configuration and command line interfaces too heavily for it to be usable by novice computer users, but this is changing rapidly.

Requirements
Hardware: Linux was originally developed for Intel based PCs, but now runs natively on almost any computer, from PalmPilots to expensive workstations. Mainframe versions are in development
Emulation: There is no need to try Linux using an emulator - if you can run an emulator, you can almost certainly run Linux natively, at full speed.

Cost and availability
Linux can be distributed and used for free, but in practice, unless you know someone with Linux you will have to pay something. A full Linux distribution can fill a CD-ROM - few people can download that much data cheaply. A better option is to buy a CD-ROM. The cheapest Linux CD-ROMs are available mail-order for just a couple of pounds. More expensive packages either fund a Linux project (usually around £20) or are value-added, containing commercial software and support.

Popularity
There are at least 7,000,000 Linux systems, but the real total is much higher. Linux is often installed 'dual-boot', so that a computer's hard disk contains Linux and the original OS such as Windows 95 or MacOS. Many Linux systems are used within businesses without official approval, quietly serving data to managers who believe their organisation is only using Windows NT.

Roles
Linux is a superb server OS, arguably surpassed only by the free BSD OSs. The geek/hacker community loves Linux, and are adding to it at an incredible rate. Some critics claim that Linux's role will extend no further than this, but this view is unsupported by evidence. Linux is becoming a good choice for general office and Internet browsing tasks, and has a small but growing number of very high quality graphics applications.

Linux is currently a poor choice for computer novices, children who want educational multimedia (there isn't any) and anyone who doesn't want to learn something new.

Software
For its key roles, Linux software is unbeatable. There is an immense range of software available, and most of it is free. Linux's similarity to Unix and the availability of cross-platorm libraries and tools makes porting to Linux relatively straight forward. The wealth of Open Source software means that software problems are fixed quickly. In fact, the Open Source software development model that gave birth to Linux is causing more excitement than Linux itself.

The Linux commercial software market is expanding fast: Oracle, IBM, Corel, Lotus, Apple and even Microsoft have announced Linux software. So far commercial software is strictly business oriented. Linux has no multimedia educational or entertainment CD-ROMs, for example.

WINE will help Linux a great deal. WINE gives Intel based Linux PCs the ability to run Windows software, without owning Windows. At present the project is still early in development, but already games such as Unreal and Starcraft can be run, and also many utilities and office applications.

Support
Lack of support is The Big Linux Myth, and is usually repeated by those who make money from supporting Windows users. Windows is rather unreliable, so there are many such people. Maybe they fear that Linux may lose them customers....

FREEBSD

FreeBSD is an advanced BSD UNIX operating system for "PC-compatible" computers.

FreeBSD offers advanced networking, performance, security and compatibility features today which are still missing in other operating systems, even some of the best commercial ones.

FreeBSD can be installed from a variety of media including CD-ROM, floppy disk, magnetic tape, an MS-DOS partition, or if you have a network connection, you can install it directly over anonymous FTP or NFS.

While you might expect an operating system with these features to sell for a high price, FreeBSD is available free of charge and comes with full source code.

AltOS now aims to cover every alternative to Microsoft operating systems. At first, each OS will have a four page guide, including a summary, an introduction to the user interface, a list of popular software, and recommended links more information on the OS.

Eventually larger, more detailed and interactive areas will develop for each OS.

Introduction
AIX is a heavy-duty UNIX based operating system designed for intensive design, server and research roles. Most AIX customers are businesses. In 1991, IBM released RS/6000 product line with AIX3 running on POWER chip set. IBM and Motorola released the PowerPC chips in 1995. All current systems are based on PowerPC chips, including some PowerPC chips that are specially designed by IBM (P2SC, Power3, RS64, RS64-II).

Features
AIX 4.3 is UNIX 98 certified, and a soft-realtime OS. It is very, very stable. AIX systems can go for months without rebooting, which is very important for servers. When coupled with IBM's HACMP software and hardware, it provides almost 24-by-7 uptime all year round. Networking features and software are excellent. It offers a secure multi-user environment. It has JFS ( Journal File System ) that offers crash-protection. The Logical Volume Manager allows very easy disk management. AIX can load device drivers and unload them at any time. It's multi-threaded up to 12 CPUs. It can address up to 2^52 bytes of virtual memory on 32-bit machines or 2^80 bytes of virtual memory on 64-bit machines. That's a lot.

AIX offers SMIT, an easy-to-use text-based system administration tool. AIX also features WebSM , a java-based Windows-like system administration tool. On the IBM RS/6000 SP, there is PSSP software that allows you to manage multiple nodes easily from one control workstation.

Requirements
Hardware: any IBM RS/6000 system or IBM SP nodes.
Minimum: 32 MB RAM, ~500 MB Disk space. 

Cost and availability
IBM includes the AIX 4.3 CDROM with selected systems. Contact IBM for further details. (Sure, it's not Open Source, but it's still cheaper than Windows NT).

Popularity
Best known as the OS in the "Deep Blue" supercomputer, the chess computer that played against Garry Kasparov. AIX is also the OS used in the world's fastest computer "Blue Pacific" at DOE's LLNL (rates at 3.9 TeraFLOPS). 

Roles
AIX is a superb server OS; marketed for scalability, reliability, security and management. It is used in file, email, web and database servers. Software includes Apache, Lotus Domino, ERP, and DB2 applications. It is also used in various scientific and engineering disciplines such as CAD, CAE, visualisation, simulation, and so on.

AIX is unsuitable for home or small business users.

Software
For its key roles, such as web serving and e-business/e-commerce, there is good range of software. Most commercial UNIX software is available for it. In addition, a lot of Open Source software can be ported fairly easily to AIX.

Support
IBM definitely supports it. As a key component of the Monterey project, more ISVs and system vendors will support AIX. Already Intel and Compaq have announced support for this project.

Prospects
In 1998, IBM, SCO and Sequent announced a new initiative called the Monterey Project. This will be ported to the new Intel IA-64 architecture as well as to future PowerPC chips. The Monterey Project will be some kind of merger of IBM AIX and SCO's UnixWare 7. Sequent will contribute their NUMA technologies. It is an attempt to unify the UNIX world. All the software will be source-code compatible with current SCO UnixWare, Linux and AIX operating systems.

Additional notes
IBM offers an RS/600 sub-product-line called the IBM RS/6000 SP. It's basically a cluster of RS/6000 servers connected via a high-speed switch. It's controlled with a special system-management software (PSSP) to make them act as one system (more or less). You can have up to 512 nodes/servers in one SP. Each node can be SMP (multiple CPUs), so that you can have thousands of CPUs in one SP system!

Introduction
The Amiga's operating system is old, and has had almost no official updates for over four years. If this had happened to MacOS or Windows they would be laughably out of date by now. It shows just how amazingly advanced AmigaOS was when it was released that even now, after so much neglect, it can still be a viable, modern OS.

AmigaOS is now owned by Gateway, who are developing a new AmigaOS based around the Linux kernel.

Features
AmigaOS features full pre-emptive multitasking, plug and play hardware configuration, an integrated GUI and low system requirements. Full CLI shell functionality and multimedia features also included.

Requirements
Hardware: A 68k based Amiga or Amiga clone, with 1MB RAM. AmigaOS can be run from floppy disks, but a harddisk is strongly recommended.
Emulation: AmigaOS can be run on UAE or Fellow emulators. A 200MHz processor is the bare minimum for useful emulation of an Amiga.

Cost and availability
AmigaOS costs about £50 for the full package. AmigaOS is also available online, bundled with an emulator in the Amiga Forever package, for about $20.

Popularity
AmigaOS still has an enthusiastic, supportive and self-sufficient user community, but sadly this community is gradually evaporating. Tied to outdated and expensive hardware, leading to few new AmigaOS users. Even hard-core fans are turning to alternatives such as BeOS, Linux and NetBSD.

Roles
AmigaOS is sill used in TV and video production roles, and is popular with hackers and BBS administrators. AmigaOS is no longer a good choice as a general home or office OS, but this could change with the release of planned consumer devices based on the next AmigaOS. AmigaOS 3.1 has software for almost any role.

Software
Despite little commercial support, AmigaOS has a huge range of software and the largest archive of software on the Internet, Aminet. AmigaOS has adequate software of every type, but is especially strong in module music, BBS, 3D and emulator software. The Amiga games scene is almost dead, but leaves a legacy of many of the best games ever released, including Quake, Myth and Descent. Classic Amiga games are the most common reason to run AmigaOS via emulation.

Support
Commercial support is almost non-existent, but there is good support from the online user community.

Prospects
AmigaOS 3.5 will soon be released by the new owners of AmigaOS, Gateway Computers. This is a modest but significant upgrade to the current AmigaOS, and brings a new, modern user interface style.

A radically improved AmigaOS is planned for release late in 1999, based on the Linux kernel. There will be another AltOS guide available with more information. Previously the next generation AmigaOS was to be based on the QNX OS. QNX have decided to go ahead with the OS without official support. This may fracture the remaining AmigaOS community between two competing "next generation" OSs.

Introduction
BeOS first appeared on the BeBox, a new PPC based computer aimed at the 'geek' market, especially Mac and Amiga users. After porting BeOS to PowerMacs and a near-buyout from Apple, Be abandoned the BeBox and concentrated on BeOS, first for Power Macs and recently for Pentium PCs. BeOS is currently available as a Preview Release, now in its fourth edition.

Features
BeOS is a modern, object based operating system, with excellent multitasking, multithreading and multiprocessor support. The ability to easily handle large multimedia files is built into the OS at a low level. An intuitive but powerful GUI and applications that are small and fast. Can be customised and configured by more technical users without being complex for average users.

At present BeOS lacks some of the features of older operating systems such as multiple monitor support and a multi-user filesystem, but these are on the way. Be Inc. are concentrating on making BeOS stable and useful on both PPC and Pentium platforms before adding major new features.

Requirements
Hardware: BeBox and PowerMacs need 16MB RAM, 150MB harddisk space. Intel Pentium and compatible systems need 32MB RAM and 150MB hard disk space. Hardware support is still limited, so check that your PowerMac or IBM compatible is supported before buying BeOS!

Cost and availability
Officially $100, BeOS can be purchased online from Be Inc for $69. People outside the US should check for a local dealer first, as postage and import duty can be costly. A cheap demonstration CD-ROM is also available.

Popularity
Considering that BeOS is still not at version one, and so all users have paid for a beta version, BeOS is selling well. The original PPC based community was rapidly dwarfed by users of the recent Intel based version. A number of large companies are planning to bundle BeOS with their PCs, in addition to Windows 98.

Roles
BeOS is usable as a primary operating system, but only just, simply because there are relatively few BeOS applications available. BeOS is still best suited to use by those who want to be at the cutting edge of OS development; programmers and geeks in other words. This is changing, though, and it won't be long before BeOS is great choice most users. BeOS is being aimed at multimedia designers, and is very well suited to this role.

Software
Software available for BeOS is of an unusually high standard, but so far there is no BeOS "killer application". The highly regarded Cinema 4D 3D software is being ported to BeOS. There is an unusually large amount of shareware and freeware for such a young OS. Many POSIX based programs (as used on Linux and the BSD clones) can be easily ported to BeOS.

Support
Be Inc and BeDepot, their online software shop, both offer surprisingly good support to BeOS users. Email queries are answered quickly and informatively, and the Be Web site contains many FAQs and mailing list archives. The BeOS user community is knowledgeable and helpful.

Prospects
BeOS is doing very well. Investment from Intel has helped Be Inc financially, but also did a lot for their reputation. It will be some time before BeOS can be market as a complete OS. When that happens, Linux will probably have an unshakable lead in business and academic markets leaving little room there for BeOS. Be Inc are concentrating on BeOS's strengths as a "media OS", pushing it towards competition with Windows NT for the creative niches such as video, music and 3D.

Additional notes
BeOS is designed to be used as a second OS if needed, so users don't lose the present OS and software on their PC. Be Inc actually market BeOS as a second OS, and encourage users to share a harddisk between BeOS and a either Windows or MacOS.

DEBIAN

Linux é software livre iniciado por Linus Torvalds e mantido por (provavelmente mais de 1000) programadores do mundo todo.

Hurd é uma coleção de servidores que rodam sobre um microkernel (como o Mach) para implementar as diferentes características. Hurd é free software produzido pelo projeto GNU.

Uma grande parte das ferramentas básicas que compõe o sistema operacional vêm do projeto GNU; daí os homes: GNU/Linux e GNU/Hurd. É claro, o que as pessoas desejam é o software; ferramentas para ajudá-las a fazer o que elas desejam, de edição de documentos ou conduzir seu negócio a jogos ou a escrever mais software. Debian vem com mais de 2250 pacotes (software precompilado arrumado em um excelente formato para facilidade de instalação em sua máquina) -- todos eles livres.

With the launch EPOC32 and competition from Windows CE, most people (including AltOS) expected Psion to continue with the Psion 3c as a budget model for a year or so, and then phase it out. Surprisingly, Psion are continuing the EPOC16 range with a new, faster model, the Psion3mx.

Features
EPOC16 is reliable (it almost never crashes), can multitask and has remarkably low power consumption. EPOC16 was designed to run on a pocket computer, using shortcut buttons and menus to control software. The interface works very well and Psion computers include a good suite of integrated apps and a versatile programming language called OPL. Printers, modems, faxes and even disk drives can be directly connected.

Networking is included, but file synchronization is a little clumsy compared to PalmOS PDAs.

Requirements
Hardware : A Psion computer.
Emulators: An official Psion 3a emulator for Windows is available free from Psion.

Cost and availability
Only with a Psion computer, see your local dealer or mail order company.

Popularity
Psion 3 computers had limited success in the USA, losing out to the Palm Pilot and Apple Newton. In Europe the Psion 3's position as market leader is being overwhelmed by EPOC32, PalmOS and Windows CE computers.

Roles
EPOC16 PCs work well as organizers like role, but can't compete with PalmOS systems for portability. EPOC16 systems are better seen as complete computer systems for someone who doesn't need or want a desktop PC too. Some people run businesses entirely on their Psion 3a, including faxing, emailing and printing!

Software
Although worldwide EPOC16 systems are less popular than PalmOS computers, their popularity in Europe has led to quite a wide variety of shareware, freeware and commercial software. The arrival of EPOC32 on faster, more powerful computers means that few new applications are produced for EPOC16.

Support
There is a good level of support from user groups and other users on the Internet, in particular EPOC16 has many newsgroups. There are strangely few Psion 3 Web sites. Psion themselves offer a mixed level of support. Connectivity software for MacOS seems to have vanished, and upgrade offers are poor or nonexistent.

Prospects
EPOC16 is old technology, but proven, reliable and well supported technology. EPOC16 will be around for quite a while, and still worth buying if you are after a cheap pocket computer.

State of Development
EPOC16 was for years the most popular, and many would say the best, palmtop computer operating system. Revolutionary when it was launched, EPOC16 continued to receive rave reviews even after the release of much more powerful Windows CE computers years later.

Introduction
EPOC32 is the recent successor to EPOC16, and the OS of Psion's top model, the Psion 5. Psion have joined forces with Ericsson, Nokia and Motorola to form Symbian, which will promote and develop EPOC32 as an OS for portable PCs, phones and other embedded applications.

Features
EPOC32 has many of the features of a full desktop OS, including true multitasking, protected memory and embedding documents within each other. EPOC32 on the Psion 5 includes a suite of applications and a programming language. EPOC32 can use a higher resolution screen than EPOC16, and accepts input from a styles. Handwriting recognition is not a standard feature, but can be added with third party software. Support for colour and Java is due in later versions. EPOC32 is not backwardly compatible with EPOC16.

Requirements
Hardware: An EPOC32 compatible palmtop. At present this means a Psion 5 or a Synergis Webphone by Philips.

Popularity
Only a couple of years old and behind EPOC16 and PalmOS, but still selling well in Europe. Not very common in USA. This should change when the EPOC32 mobile phones are launched, especially in Europe.

Roles
The Psion 5 is more like a pocket sized laptop than a PDA, as it can be used to replace a desktop PC completely. Creating documents, Web browsing, e-mail , faxing, printing, backup and networking are all possible without a desktop PC. Of course, EPOC32 on the Psion 5 includes applications for all PDA type tasks such as handling appointment, contacts and accounts.

Software
There is a smaller range of software available for EPOC32 than for EPOC16 or PalmOS, but EPOC32 is not lacking in software. A Spectrum emulator and Doom clone are two of the more entertaining titles available.

Support
There is a good level of support from user groups and other users on the Internet, in particular EPOC16 and 32 have many newsgroups. There are few Psion 5 Web sites. MacOS compatible connection software costs extra.

Prospects
Symbian could well make EPOC32 a new industry standard, as Ericsson, Nokia and Motorola currently dominate the European mobile phone market.

Introduction
FreeMiNT is a unique hybrid of Unix and TOS, the Atari ST operating system. Originally planned as a soft loaded TOS extension that could facilitate porting GNU software to the Atari ST series of computers, FreeMiNT has evolved into a fully featured replacement OS.

FreeMiNT is maintained by the community of FreeMiNT users, and, specifically, by the kernel team; several programmers who do any necessary kernel development. The same community also does any related work, such as writing utilities, porting GNU software, preparing any necessary documentation and system distributions.

Features
FreeMiNT features pre-emptive multitasking with adaptive prioritisation, memory protection, virtual filesystem, multithreading, multiuser support, and interprocess communication mechanisms such as signals, messages, FIFOs, shared memory. Loadable extension modules provide additional devices such as virtual text consoles and powerful, Unix-like network support.

The built-in filesystem drivers allow access to FAT12, FAT16, VFAT and FAT32 filesystems. Soft loaded modules provide Minix V2 and ext2 filesystems.

All standard Unix CLI shells, such as tcsh, bash, ksh, zsh etc. can be used. The GUI is not integrated but the user can choose between a multitasking GEM and X11R5. 

In addition, FreeMiNT is still able to run most ordinary TOS software.

Requirements
Hardware: FreeMiNT can be run on any Atari ST compatible hardware (including clones) equipped with 68000, 68010, 68020, 68030, 68040 and 68060 processors. Since the system mainly uses soft loaded devices to access hardware, the required Atari ST compatibility is in fact reduced to the presence of a TOS compatible BIOS.

In a basic set-up the system is satisfied with a 68000 processor Atari ST with 2.5 MB of RAM and a floppy drive, though a hard drive is recommended. A full installation may require 16 MB of RAM, a hard drive and a 68030 based machine running at 16 MHz (which is an equivalent to an average Atari Falcon030). A floating point coprocessor is supported but the system does not require it. Memory protection currently requires a 68030 compatible memory management unit.

Emulation: FreeMiNT can also run on top of the STonX emulator and on top of MacOS on a 68k Macintosh computer by using a program called JET.

Cost and availability
Free, apart from the time needed to download the distribution and install it. The most popular distribution is available on most popular FTP sites with Atari software.

Popularity
FreeMiNT still has many enthusiastic users and creative programmers among owners of TOS based computers, and seems to be gaining new users from among the Atari community. Sadly, these new users do not come from outside of the Atari world - FreeMiNT gains users out of those who have used other Atari based systems.

Although the community of Atari users is gradually evaporating, it may be possible that this process will slow down. New, relatively cheap FreeMiNT compatible hardware appeared on the market in early 1998: an Atari clone supplied with two operating systems: TOS 4.50 and FreeMiNT using N.AES as a GUI.

Roles
In the days when Atari was still alive, FreeMiNT was never used as a mainstream OS for Atari hardware mainly because of doubtful TOS compatibility and the poor stability of early MiNT and MultiTOS versions. Though now FreeMiNT has been greatly improved and is a rock solid OS, it is still not a good choice for an office OS (although several GEM based office applications exist and run under FreeMiNT) mainly because the existing office software cannot exchange data with the PC world without difficulty. Also, it does not perfectly serve as an OS to run entertainment software, because most of popular Atari games refuse to run under FreeMiNT.

GNU's Not Unix!. The GNU Project was launched in 1984 to develop a complete free Unix-like operating system--the GNU system. Variants of the GNU system, which use the kernel Linux, are now widely used; though these systems are often referred to as ``Linux'', they are more accurately called GNU/Linux systems.

JeniOS started as an idea whilst I was studying for a degree in Computing at Bolton Institute. The idea was mainly derived from the success of the Linux operating system. I wanted to create an operating system from the ground up with out any legacy code or design methodologies. Also the disadvantage of Linux is that it is so hard to set-up (well that may have changed considerably now) and use with it being a UNIX clone. Instead, JeniOS was originally intended to be a completely new operating system without any of the disadvantages of UNIX but all the advantages. Another operating system that is similar in form to JeniOS is BeOS. However BeOS is not free, and you can not obtain the source code for free.

MacMinix is the Macintosh version of MINIX. MINIX is a Unix clone, which contains no AT&T code. This means that the source code can be made publicly available. MacMinix was very poorly supported, and never kept up with the PC version. Now both products appear to have been abandoned.

Mac OS 9 is the ultimate upgrade for anyone on the Internet or anyone who wants to be. With more than 50 powerful new features, Mac OS 9 offers a full suite of capabilities for new and advanced users. At work, home, or school, there’s no better way to get the most of your Macintosh computer and the Internet.

Introduction
New Deal is a little known commercial operating system and office suite based on GEOS. Most operating systems advertise their compatibility with the latest hardware, but New Deal is different; it aims to breath new life into old PCs that just can't keep up with more resource hungry OSs.

Features
New Deal is fast, resource efficient and reliable, features it has inherited from GEOS, its ancestor. New Deal provides a multitasking GUI environment even on 286 computers, and includes a suite of fully functional office applications. The user interface resembles a combination of Windows 3.1 and Windows 95, so it will be familiar to most users. New Deal sits on top of a DOS OS, such as DR-DOS, FreeDOS or MS-DOS, but replaces most DOS functions with its own.

Requirements
Hardware: Any 286 or higher based PC, with at least 640K of RAM.
Emulators: Any emulator that offers complete PC hardware compatibility should work, but AltOS hasn't tested this yet.

Popularity
Small, but growing. AltOS has had many requests from enthusiasts to feature New Deal, more requests than for any other OS.

Roles
New Deal is perfect for returning an older PC to active use as a word processor and home accounts system. The web browser is functional, but lacks many features some sites may require.

Software
Almost all New Deal compatible software is available on the New Deal Web site, but a computer running New Deal can also run DOS software and some GEOS applications, so in practice the choice is much wider. Most software a New Deal user will ever need (or be able to use on their hardware) is included with the OS, which is excellent value.

Support
New Deal Inc. offer good support to New Deal users, but there is little other information available on the Web. Fortunately the nature of New Deal means that users should have few problems.

Prospects
With enough publicity New Deal Inc should get the success they deserve. There are many computers that are currently being wasted because they can't keep up with Microsoft's slow, bloated software. New Deal is an ideal solution for the users of "obsolete" PCs who want modern, supported software.

Additional notes
New Deal is an almost MacOS-like system, and is a good choice for computer novices and people who don't want to 'get their hands dirty' with technical issues. AltOS hasn't tested New Deal yet, but hopes to soon.

Introduction
PalmOS is the operating system used by the Palm Pilot series of palmtop computers. The Palm PDAs continue to set the standard for light weight, palm sized computers. PalmOS looks bland and dated compared to the more recent Windows CE, but users and reviewers love it because of this simplicity: PalmOS performs very well.

Features
PalmOS was designed for use in a small, inexpensive shirt pocket sized computer, and it shows. The user interface is clear and unencumbered. PalmOS pen based input uses a simple handwriting recognition system that requires users to adapt their style, but saves on processor and battery resources. PalmOS is stable and has very low power consumption. Easy synchronizing with desktops is included, and information can be shared between PalmOS computers using infrared. PalmOS is usually stored on an upgradeable ROM.

Requirements
Hardware: Palm or a compatible such as the IBM WorkMate. PalmOS really requires a desktop computer too, it is not really meant for independent use.
Emulators: copilot lets PC, Mac Linux and BSD users run a virtual Palm Pilot.

Cost and availability
Only with a PalmOS computer. Prices vary, check with local dealers.

Popularity
PalmOS is still the best selling and most popular palmtop OS.

Roles
PalmOS effectively created the role of palmtop PDA. Unlike the Psion 3, Psion 5 and Newton, PalmOS isn't meant to be a complete pocket computer, as it lacks independent storage, backup and printing. Instead, PalmOS computers are meant to be regularly synchronized with desktop or laptop computers. Unlike a Psion or Newton, a PalmOS computer can be carried in a shirt or trouser pocket, and is therefor always be available. PalmOS is popular as an 'executive organizer' for busy professionals, an industrial data gathering tool, and as a near essential geek accessory.

Software
PalmOS has more software than any other pocket computer. Most of the software is available on the Internet as freeware or shareware. Even Web browsers and 3D arcade games are available. There is good support for synchronizing with desktop OSs too. Windows, MacOS, Linux, BSD clones and Amigas can all share data with PalmOS.

Support
Support for PalmOS users on the Internet is good, with many online resources. 3Com seem to provide better long term support for users than competing companies; they sell upgrades to older PalmOS computers instead of forcing users to buy new computers, for example.

Prospects
PalmOS has a bright future, but also has a bright present. Windows CE has failed to dislodge PalmOS from its market dominance. A new range of PalmOS based PDAs from 3Com and other companies, including devices with built in mobile phones, pagers, fax machines and wireless email, should make PalmOS more popular still. 3Com seem to be very cosy with Apple recently, and there are persistent rumours of collaboration between the two companies.