Psion Epoc SIS Installation Files

The best software install system.

Installing programs automatically, from Psion or PC.

An EPOC software installation system file, with a .sis extension, is the method by which programs are distributed for EPOC based Psion and other organisers. It makes a package of all the installation files, and ensures they are installed in the right places. It also lists them in the Control Panel so they can be uninstalled later.

How to Install

If your Psion is connected to a Windows computer via EpocConnect or PsiWin 2.1 and later, you can usually just double click a .sis file. The program will be installed over the serial link.

If you transfer the .sis file to a Psion via IrDA or Compact Flash, or download it from the internet using a Psion, you can just double tap the .sis file in the Psion. Or you can open the Control Panel, and use the Add New option.

A few programs install better direct on the Psion. If you ever have problems starting a program installed via PsiWin, transfer the .sis file to the Psion instead, and run it on the Psion.

Residual .sis file stubs are created in the system\install folder during installation. They provide information for the control panel list of installed programs, and information for safely removing applications. Do not delete them manually.

If a program fails to fully install, it will be marked partial in the control panel list of installed applications. Removal and reinstall is recommended.

Older Programs

Older programs may have to be added manually if no .sis file is provided. Follow the author's directions. If there are no instructions, try making a new folder in the System\Apps directory under the name of the program, and put all the program files in that. Data files should however not be kept in the system folders.

Psion 5 Needs Extra Program

If you have a old Psion 5 (classic ER3), you may not have an Add New icon in the Control panel. If not, you need to add to your Psion a piece of software called instexe.exe, and run it. That will add the missing component. This is normally done automatically as part of one of the Message Suite upgrades. The Add remove components are present in the ROM for ER5 systems, and do not need to be added.


You can use the Control Panel Remove option to delete software added using a .sis file. This should not normally remove documents you have created with the application, however these will no longer be identified, and will not be automatically opened.


Newer build versions of .sis applications will automatically replace older build versions. The Epoc Add remove program will not allow older .sis builds to replace a newer version (if you need to do that, you must remove the current version). The Windows version will permit overwriting newer versions, but will require confirmation. The build number (included by the original programmer), not the file date, is used to decide which file is newest.

Makesis Creates the Install .sis File

After writing a program on a PC using the EPOC Emulator, programmers prepare a .pkg file containing the locations on a PC of all the application files, and the target locations on an EPOC machine. They use the PC based Makesis tool which takes the information in the .pkg file and compresses all the applications and creates a .sis file. Use Makesis -h for a usage output.

The .pkg File Format

The .pkg file is a text file that tells which languages are supported, an installation header with build numbers, names of various files to install, and comments. Some of these may be left out, but here is the contents of a typical file, which must be in this order.


Languages to be used, all given two letter codes. I've used UK English, American English and Australian English, but there are several dozen that are not English.

Installation Header
#{"Good App", "Great App", "Bonzer App"},{0x1000666},1,1,0

The Component UID number is assigned by Psion. Last come the major and minor numbers, and the (optional) variant number.

"\epoc32ex\new\"-"!:\system\apps\myapp\", arguments

The !: is used to indicate the application can be installed on any EPOC drive. If a specific drive must be used, it must be specified. This type of line would be repeated for all the resource and other files needed.

Four arguments can be specifed. FF is the standard default. FT is a text file whose contents will be displayed like a ReadMe during installation (but will not be installed). FN is a file which doesn't exist, but will be created by the application, such as an .ini file for preferences. This is to stop them being lost during an upgrade. FR is a file which will install and run during install or removal.

FT and FR arguments can be modified. If FT is specified, then the TC default means a Continue button appears. TS means Yes and No buttons appear, and no will stop the next file installing. TA gives a Yes and No button, but a no aborts the install. If FR is specified, the default RI means run during install. RR means run during removal. RB means run on stall and removal.

A possibly shared OPX file should have a separate .sis file.

Language dependent files

Only one file will be installed, depending on the selected language.

Requisite Files
(0x100002c3),1,2,5, {"Standard C Library"}

These files must already be present on the EPOC machine, in either the same or a more recent version, or installation will fail. The variant number is ignored. The user will be warned if a required file is being removed. These files are identified by the UID not the name.

.sis Files

SIS files can be specified to be installed.

More Details about SIS

The Psion software development kit system documents include an excellent set of notes regarding SIS. If you have installed the free OPL SDK on a Windows computer (which I strongly encourage, as it includes the Psion Emulator) you will find web pages in /sysdoc/ask/Makesis

This site will look much better in a browser that supports W3C web standards but it is accessible to any browser or internet device, including Psion Web and similar PDA or limited browsers. Netscape 4.x users - turn Style Sheets off. Your style sheet support is too broken to use (sorry). -> epoc -> miscellaneous -> sis install

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