~04/1995
Computers with amnesia ? All Acorn computers since the Master 128 have relied upon configuration settings being stored in a memory device which is kept powered even when the computer is switched off. This is usually, though incorrectly, referred to as CMOS RAM. With the exception of the Master Compact, the power to maintain the settings (and the real time clock) comes from batteries inside the computer. The Master Compact used a device called an EEPROM (an Electrically Erasable Programmable Read-Only Memory) which did not require a battery, but only allows a limited number of write operations - where a Master Compact is failing to retain its settings this device may need replacing. On most ARM based 32 bit systems the battery is a NiCad (Nickel Cadmium) cell, which is trickle charged whilst the computer is switched on. This can mean that after a machine has been unused for a very long period it may need to be left on for several hours to recharge the battery. These batteries should not need replacing. The Master 128, Archimedes 305/310, Archimedes 440 and Archimedes 400/1 series all use a battery pack with conventional battery cells. The recommended replacement interval for these batteries is annually, however they will often work for much longer. Even now, it is not uncommon to see a 305/310 still on it's original pair of batteries! If you've got one of these computers - when were your batteries last changed ! As with all devices powered by batteries you should replace them at recommended intervals, and avoid leaving discharged batteries in situ since corrosive substances may leak from the battery and damage the surrounding area. Failing batteries can produce many strange symptoms, including incorrect time/date values, and the random disabling of modules/sideways ROMS as the locations used to hold the *UNPLUG settings vary because the battery can no longer consistently maintain sufficient power. This usually results in some quite strange errors - for example a Master 128 may start up using a different filing system to normal, or a RISC OS computer may fail to start up the desktop. Ethernet based AUN networks If you are getting poor performance from such a network you should check whether the Broadcast Loader is enabled on any Ethernet based stations. The Broadcast Loader should be disabled in these circumstances using *Unplug BroadcastLoader in a boot sequence. Look it's magic! The filetype system employed in RISC OS can be used to save memory and automatically load specific applications as they are required. You do not, for example, have to have !Edit loaded all the time to be able to double-click on a text file. Provided that the application has been seen in a directory viewer before you double-click on a file which can be handled by that application the application will be loaded when it is needed. There are also some ramifications of this: if a file does not have its usual icon, but instead has a blank square, the relevant application has not been located yet in a directory viewer. There are also some filetypes allocated to generic files (such as CSV - comma separated value) which are commonly used for interchanging data between various application - these should not be explicitly claimed by any application.