Latest news

JPEG bounty captured, parrot unharmed

Posted by Steve Revill Thu, 02 Jun 2016 20:06:00 GMT

Ahoy there! Any land lovers who watch the recent changes to RISC OS will have noticed a recent wave of activity in the area of JPEG, marking the completion of this bounty.

JPEG images are most commonly encountered from digital cameras or similar real life pictures. They achieve very high compression ratios by relying on the design of the human eye (the one without a patch over it) where brightness detail is more important than colour detail.

Posted in Miscellaneous, New component, Community | 4 comments

Get connected with ROOL

Posted by Steve Revill Wed, 06 Apr 2016 09:20:00 GMT

The bonus binaries launched last October have just gained a whole extra utility application, !Connector, originally written by Andreas Zieringer for the Archimedes.

Connector¹ is a terminal emulator program which supports the XModem, YModem, ZModem and plain ASCII protocols to transfer files and data with a remote terminal.

Posted in New component, Community | 1 comment

Important software compatibility notice

Posted by Steve Revill Sun, 05 Jul 2015 09:54:00 GMT

Starting from tomorrow, July 5th, the Iyonix, OMAP3, OMAP4 and Raspberry Pi development ROM images will be making use of “zero page relocation”, a change to the RISC OS memory map which moves the kernel’s “zero page” workspace away from address zero and up to the high end of the memory map. This greatly increases the system’s resilience to a common type of software bug known as a “null pointer dereference”. However, there is a catch: because the OS has always had memory mapped to address zero, large amounts of RISC OS software contains cases of “harmless” null pointer dereferences where the code reads from page zero and then does something insignificant with the result (usually ignoring it completely). With the new memory map, these programs will most likely cease to operate, exiting with a data abort as soon as they try to access page zero.

Since relocating zero page is very beneficial to the stability and security of the OS, the goal is to have the feature enabled for all future stable releases, starting with RISC OS 5.24. But due to the large amount of buggy software out there we can’t simply turn it on and be done with it – we need to have a transition period in which developers can fix their code without worrying about the fact their compilers, text editors, etc. are buggy too. We also need a way for regular users to get involved with the testing process.

With that in mind, we are putting into effect a two-phase testing process:

Phase 1 of the testing process begins tomorrow. Zero page relocation is enabled, but a compatibility/logging module (“ZeroPain”) is provided to you in order to allow most buggy software to continue to run unmodified. ZeroPain traps most attempts to read page zero and emulates the operation, providing a safe level of compatibility with the old memory map. And for any page zero access which it emulates, it adds an entry to a log file so that the user/developer is aware of the issue.

Phase 2 of the testing process is due to begin on 1st Jan, 2016. ZeroPain will refuse to run on any ROM built on or after that date. This will help to ensure that any previously unnoticed bugs are found and fixed prior to the release of RISC OS 5.24.

ZeroPain can be found within each ROM download archive. Make sure to install it before installing the new ROM, otherwise your system may not boot correctly. Please help ROOL make RISC OS a better OS by testing all your software and reporting any issues you find to the developers.

High processor vectors and IOMD support

Modern ARM CPUs support a feature known as ‘high processor vectors’, whereby the processor vectors are moved from their old location at &0 to a new location at &FFFF0000. Zero page relocation within RISC OS makes use of this feature – without it we would still need some memory mapped to address zero in order to contain the processor vectors. Although high processor vectors is currently a requirement for zero page relocation, this is likely to change in the future, in order to support zero page relocation on the IOMD (RiscPC/A7000/RPCEmu) build of RISC OS.

OS_PlatformFeatures 0 can be used to determine whether high processor vectors are in use (flag returned in bit 20). Software which needs to interact with the processor vectors directly should use this to determine their location. The address of the processor vectors should not be used to infer the address of the zero page workspace, and vice-versa.

Apart from the change in location, the processor vectors continue to operate as normal – so for FIQ handlers, you can still rely on having 228 bytes of space available for your handler code (from &FFFF001C to &FFFF00FF inclusive). Also, for future compatibility, code should not assume that the processor vectors are readable from user mode – regardless of whether high processor vectors are in use or not.

Unaligned loads

Another change that is planned for RISC OS 5.24 is to re-enable support for unaligned loads/stores on ARMv6+. For the past few years this feature has been disabled by default, to protect you against potential compatibility issues with software which assumes the older ARMv5 “rotated load” behaviour is in effect. But we believe the time to re-enable the feature is drawing near – expect to see it happen sometime during the zero page relocation testing process. By re-enabling support for unaligned loads/stores the performance of some OS operations will be improved, and third-party software aimed at ARMv6+ can more easily make use of the feature.

Posted in Miscellaneous, New component, Community | 1 comment

RISC OS 5.22 stable is now available

Posted by Steve Revill Sat, 25 Apr 2015 12:14:00 GMT

RISC OS Open Limited (ROOL) are pleased to announce the much anticipated latest stable RISC OS release, it incorporates a massive 454 changes for the Tungsten platform (used in the IYONIX pc from Castle Technology), 484 changes for the OMAP3 platform (used in the ARMini from RComp), and 423 changes for the IOMD platform used in the Acorn Risc PC/A7000/A7000+.

For the first time the stable release includes the OMAP4 port, a Cortex-A9 processor used in the PandaRO from CJE Micros and ARMiniX from RComp.

This software is subject to continual improvement and work has already commenced on RISC OS 5.23! Using the convention of even numbers for stable editions and odd numbers for development editions, users can feedback any issues seen to make it into the next version.

Show your support

Putting together this latest release takes considerable time and effort, not just on the coding, but the testing, co-ordination, documentation and other administration that nobody ever sees. Downloads also use the bandwidth allocation for the server that this website runs on.

Please consider making a small donation to show your appreciation:

Posted in Press release, New component | 4 comments