27/01/95 Questions and Answers --------------------- Where's my nearest Acorn dealer? As the list of Acorn dealers is constantly changing, there is no fully comprehensive up to date copy on paper, although paper copy detailing the majority of dealers is available. Customer Services maintains an on-line database of dealers and their addresses, from which we can generate a comma-separated variable (CSV) list suitable for loading into most other databases. This list is available via anonymous ftp as ftp.acorn.co.uk:/pub/documents/dealers/uk, and by download from the "Acorn support" areas of Arcade (Tel: +44 181 654 2212) and Digital Databank (Tel: +44 1707 329306) BB systems. In addition, a plaintext list of overseas dealers and distributors is available as ftp.acorn.co.uk:/pub/documents/international. If you don't have a modem, you can always ask us! MODE in BASIC: The Next Generation ---------------------------------- The way in which modes are specified on the Risc PC has been changed in order to allow the new extended range of modes to be accessed; modes now have associated strings, instead of just numbers. A typical BASIC command to change mode would now be MODE "X800 Y600 C32K EX1 EY1 F50" which can be broken down into: X800: 800 pixels horizontally Y600: 600 pixels vertically This is a fairly common resolution; alternative choices are determined by the Monitor Definition File. C32K: 32016 colours. Other common options, depending on the resolution of the mode and VIDC bandwidth, are: C256 256 colours G256 256 grey levels C16M 16392192 colours This last level is actually better than the average human eye can resolve (the eye has been shown to be able to chromatically resolve roughly 15.4 million hues). EX1 EY1: Horizontal and vertical "eigenvalues" of 1. These eigenvalues relate to the method of mapping of OS units onto pixels. If EX1 is increased, the most obvious effect is that the size of windows, text and icons decreases in the X direction; this effect can be used to produce a Desktop with an apparently larger work area. However, if the eigenvalue is set to a high value, parts of the display may "go missing" owing to the mapping producing pixel overlap. F50 50Hz frame rate. This string representation of screen modes can be accessed from the "Mode" entry on the icon bar menu belonging to the standard screen control icon. Many "old" style screen mode numbers can still be used; modes 0, 1, 8, 9, 11, 12, 13, 14, 15, 25, 26, 27, 28, 41, 42, 43, 44, 45, 46, 47, 48 and 49 are explicitly defined, and modes close to the resolution of other "old" modes may be defined in MDFs. Somewhere In Time ----------------- The first 32 bit Acorn machine to use a rechargeable battery to power the real-time clock and CMOS RAM was the A3000. The batteries used are considered to have a lifetime of five years; this means that the batteries on many A3000s are reaching the end of their lifespan. If your machine appears to reconfigure itself on power-up, or the real-time clock shows a decidedly unreal time, you need to contact your dealer for a battery replacement. The CMOS uses 2 bits to determine the relationship between the current year and the next leap year, so you may also find your reset clock defaulting to 1991 by virtue of a leap year having occurred since RISC OS 3.1 was released; a reset to 1995 using !Alarm will fix matters, and your clock will still roll over properly to 1996 at the end of this year! World Wide What? ---------------- Probably the most talked-about method of accessing Internet-based resource over the last couple of years is World Wide Web, particularly when connected with a new generation of graphical hypertext-based client programs such as xmosaic. Web documents are served using the HyperText Transfer Protocol (http), and addresses of Web documents are specified using Uniform Resource Locators (URLs). A URL has the syntax: :///{/ |} Currently there are two freeware browsers available for RISC OS, and several companies are working on commercial packages which will also include browsers. During November Acorn opened www.acorn.co.uk, our own server containing a range of product and technical information, so we could determine if users would find such a service valuable. 17638 accesses and plenty of constructive email convinced us we were doing the right thing! Currently www.acorn is being overhauled and re-worked in readiness for a full opening, and hence is unavailable. Some concern has been expressed over the www.acorn alias having been removed from our DNS; this was done because attempted logins to the blocked service were not generating timeouts correctly, resulting in hung processes at the client end.