Granny's Garden

01 · Memory

Bug: on this disc, Part 1 runs out of memory before Tom

Each program was written to move itself down to &0E00 when it is loaded higher, as a disc system's workspace makes it. On this disc that test is turned off, and Part 1, left at &1900, stops with No room before the end.

The first line of each program was a test, IF PAGE<>&E00 GOTO 3280 (2590 in Part 2). The lines it goes to select the tape filing system, copy the program down to &0E00 four bytes at a time and run it there, which gives it 2,816 bytes more. The second line then writes a REM over the first, so that the program, running at &0E00, does not test again. Both files on this disc were saved after such a run: their first lines are REMs, and CHAIN runs each program where the disc system loads it, at &1900.

Part 1 has about 1,000 bytes there when it starts, and its variables and BASIC's stack need about 1,600 more as it goes. It stops at the pond, or on the stairs by the route through the house, and No room is the one error ON ERROR cannot catch (starting again), so the game ends at BASIC's prompt. Part 2 is smaller and runs to its end either way. Typing LOAD"GRAN1" and then GOTO3280 runs the program's own move and gets round it.

This disc is most likely a copy of the tape, which would make the bug the copy's. The teacher's booklet says 4Mation's disc starts with SHIFT and BREAK and then will load and run automatically, but this disc has no boot file, and SHIFT-BREAK does nothing. The booklet calls the programs GRANNY1 and GRANNY2, names the disc system would have taken, where this disc has GRAN1 and GRAN2. On tape, it says, The initial program will load and run followed, automatically, by the main program, and Ready to start? comes following the title pages; this disc has no first program, and Ready to start? is its first screen. The booklet also tells the owner of a machine with a disc interface who is loading the tape to type *TAPE first, which is the machine the move down to &0E00 was written for. The REM over each first line is what a run of the tape's programs leaves behind. No disc of 4Mation's has been compared, so this rests on the booklet.

02 · The giant

Bug: answer the giant "maybe" and the hill turns into the forest

The giant on the hill asks Shall I eat you?

After Maybe, then Y: the forest's words under the hill's picture. Played in jsbeeb on 14 October 2026.

PROCgiant asks again when the answer is neither yes nor no, by calling itself. When the inner call ends at Y, it returns to the end of the outer call's last line, line 2090, and BASIC carries on to line 2100. That line is DEF PROCfor, the forest, and BASIC passes over a DEF it meets on the way as though it were a REM, so it runs the forest's lines inside PROCgiant: the words about the creepy forest appear under the hill, no stone is offered, and the map then says the player is at the hill.

03 · Lost without being told

Bug: the Land of Mystery can be lost without the game saying so

The Land of Mystery has one key, one cake and one chance at the castle door. Three choices use one up, and the player can then walk the map for good without being able to finish.

The castle was meant to let a friend back in. Its flag fed%, which would say the keeper has been given the cake, is set FALSE at line 180 and never set TRUE, so the keeper's welcome for a returning friend, at line 2500, is never shown.

04 · DELETE

Bug: one DELETE too many and the answer no longer matches the screen

A DELETE pressed when the answer is empty still counts, and PROCi's count of letters falls one behind the screen. From then on each DELETE takes a letter too many off the answer, or none at all.

PROCi, the input routine every answer goes through, keeps the number of letters in l, and a DELETE does l=l−1 and in$=LEFT$(in$,l). A DELETE in an empty field still counts, so l becomes −1, and stays one less than the letters on the screen. Each later DELETE cuts the answer to l letters, one fewer than the screen keeps; when l is below zero it cuts nothing, because BBC BASIC's LEFT$ with a negative length gives back the whole string (tried on its own: LEFT$("AB",-1) is AB). A child who presses DELETE once too often and then corrects a mistake sees the right word on the screen while the game reads another: Snow, typed that way at the password, is Snw, which holds no no.

05 · The Giant's garden

A bee hurt in the wood cannot chase off the dog

In the Giant's garden each creature helps at one stage of the way to Tom. The bee is the only one that can get past the Giant's dog, and if it was called in the wood before, it will not.

Calling the bee in the wood sets be to 1 until the program starts again. At the dog, only an unhurt bee chases the dog away, and every other creature brings the Witch, so a player who tried the bee in the wood cannot reach Tom until the Witch has sent them home. The bee says it must go to the doctor, and the toadstool says You will have to try again., as it does after any creature that cannot help in the wood. Nothing says that the bee is needed later, and the dog is two stages on.

The trap is meant. The teacher's booklet warns that Each creature can help once only although this information is not given to the children. The code has a reply written for the hurt bee at each stage after the wood, Have you forgotten what happened? A nut made my nose bleed. The doctor has told me to rest. (line 2750), and the butterfly, which a nut can hurt there too, has one of its own (I think you have forgotten something., line 2690). Once it has carried the player over the pond, the butterfly says I have already helped you once.

06 · The booklet's questions

The questions the teacher's booklet set, answered from the code

The teacher's booklet ends with mysteries for a class to talk over. The code answers several of them, and the booklet's author answers one himself.