If RAMDOS is relocated into one of the extra banks of memory, the 2K buffer used by CAT and LOAD is fixed immediately below RAMDOS, occupying roughly &7000-&7800. This buffer normally resides immediately below HIMEM but this means that the buffer would be in danger of over-writing RAMDOS. This is because the bank used by RAMDOS is switched in to occupy &4000-&7FFF whenever disc functions are used, so that the 2K buffer over-writes this bank whenever HIMEM is between &4800 and &8800. To avoid this, the buffer is fixed to a permanent position occupying the 2K immediately below RAMDOS. The position of this permanent buffer address can be changed by poking a new value into &BE3B/C after RAMDOS has been initialised. A value of zero will make the buffer lie immediately below HIMEM as normal. |