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Programming:Undo delete of file

2010-04-14T19:49:03Z

Tlb: Created page with 'If you accidently delete a file from disk, there is a way to make it visible again. ''Important!'' Don't not save anything to disk after deleting because it will be impossible t…'

If you accidently delete a file from disk, there is a way to make it visible again.

''Important!'' Don't not save anything to disk after deleting because it will be impossible to recover your files then.

type this:

poke &a701,229
cat

now you will see all the deleted files that are still stored on the disk.
you can '''load"''' a basic file, then type

poke &a701,0
save"filename

and it will be saved again.

For other non-basic files you'll have to use a disc tool like discology.

This is how it works:

This poke does the same as the ''|user'' command from amsdos. The ''|user'' command can only access user 0 to 15.

When you delete a file mit ''|del'', AMSDOS rewrites the user level of the file with number 229. So, when you change to this level, you will see the deleted file again.

Source Codes

2010-04-14T19:41:32Z

Tlb: /* File access */

[[Category:Programming]]
''This article contains source codes and programming examples. You may also have a look at''
* [[Programming software]]
* [[BIOS Functions]]
* [[Technical documentation]]s
* [[Locomotive BASIC]]
* [[Type Ins]]

== Assembler ==
*[[Z80_-_undocumented_opcodes|Z80 - undocumented opcodes]]
*[[Where to learn?]]

== Algorithms ==
*[[Programming:CPC OS floating point routines|CPC OS floating point routines]]
*[[Programming:CRC16|CRC16]]
*[[Programming:CRC32|CRC32]]
*[[Programming:Integer Division|Integer Division]]
*[[Programming:Integer Multiplication|Integer Multiplication]]
*[[Programming:Ultrafast Multiplication|Ultrafast Multiplication]] by [[Prodatron]]
*[[Programming:Fast Square Root|Fast Square Root]]
*[[Programming:Fast 16 bit Square Root|Fast 16 bit Square Root]] by [[User:Executioner|Executioner]]
*[[Programming:Filling memory with a byte|Filling memory with a byte]]
*[[Programming:Square Root|Square Root]]
*[[Programming:Precalculated square|Precalculated square]]
*[[Programming:Random Number Generator|Random Number Generator]]
*[[Programming:Quicksort|Quicksort]]
*[[Programming:Sin/Cos calculation|Sin/Cos calculation]]

== CP/M ==
*[[Programming:A simple 'Hello World' program for CP/M using BDOS|A simple 'Hello World' program for CP/M using BDOS]]
*[[Programming:A simple 'Hello World' program for CP/M using BIOS|A simple 'Hello World' program for CP/M using BIOS]]
*[[Programming:Executing firmware functions from within CP/M 2.1|Executing firmware functions from within CP/M 2.1]]
*[[Programming:Executing firmware functions from within CP/M 2.1 or CP/M plus|Executing firmware functions from within CP/M 2.1 or CP/M plus]]
*[[Programming:Executing firmware functions from within CP/M 2.1|Executing firmware functions from within CP/M 2.1]]
*[[Programming:Executing firmware functions from within CP/M plus|Executing firmware functions from within CP/M plus]]

== CPC Plus ==
*[[Amstrad CPC plus sprite format]]
*[[Programming:Convert CPC sprites to Plus hardware sprites|Convert CPC sprites to Plus hardware sprites]]
*[[Sprites Multiplexing]]
*[[Programming:CPC Plus Hardware Sprites|Hardware sprites]]
*[[Programming:CPC Plus Horizontal scroll|Horizontal scroll]]
*[[Programming:CPC Plus RLE Hardware Sprites|RLE hardware sprites]]
*[[Programming:CPC Plus Screen Splitting|Screen splitting]]
*[[Programming:CPC Plus Vertical scroll|Vertical scroll]]
*[[Operation of Z80 interrupt mode 0 in the CPC plus design]]
*[[Programming:Simple Raster Example 2 (uses CPC plus features)|Simple Raster Example 1 (uses CPC plus features)]]
*[[Programming:Simple Raster Example 3 (uses CPC plus features)|Simple Raster Example 2 (uses CPC plus features)]]
*[[Programming:Unlocking ASIC|Unlocking ASIC]]

== Devices ==
*[[Programming:CPC Booster|CPC Booster]]
*[[Programming:Digiblaster|Digiblaster]]
*[[Programming:Program to save the ROM of the Multiface 2|Program to save the ROM of the Multiface 2]]
*[[Programming:SYMBiFACE II|SYMBiFACE II]]

== File access ==
*[[Programming:An example to read a file byte-by-byte|An example to read a file byte-by-byte]]
*[[Programming:An example to write a file byte-by-byte|An example to write a file byte-by-byte]]
*[[Programming:A simple file copier using firmware functions (copies byte-by-byte)|A simple file copier using firmware functions (copies byte-by-byte)]]
*[[Programming:Loading a file|Loading a file]]
*[[Programming:Saving a file|Saving a file]]
*[[Programming:Unlocking a protected basic file|Unlocking a protected basic file]]
*[[Programming:Undo delete of file|Undo delete of file]]

== Floppy disk ==
*[[Programming:A simple disc copier using BDOS functions|A simple disc copier using BDOS functions]]
*[[Programming:A simple disc formatter using BDOS functions|A simple disc formatter using BDOS functions]]
*[[Programming:An example loader|An example loader]]
*[[Programming:Catalog a disc and retrieve a directory|Catalog a disc and retrieve a directory]]
*[[Programming:Detecting an Amstrad or Vortex disc controler|Detecting an Amstrad or Vortex disc controler]]
*[[Programming:Formatting a track on a disc|Formatting a track on a disc]]
*[[Programming:Reading a sector from a disc|Reading a sector from a disc]]
*[[Programming:Reading and writing the boot sector of a SYSTEM/VENDOR disc|Reading and writing the boot sector of a SYSTEM/VENDOR disc]]
*[[Programming:Writing a sector to disc|Writing a sector to disc]]

== Graphics ==
*[[Programming:Display a 8-bit number in binary|Display a 8-bit number in binary]]
*[[Programming:Display a 8-bit number in hex|Display a 8-bit number in hex]]
*[[Programming:Display a byte as a 3-digit decimal number|Display a byte as a 3-digit decimal number]]
*[[Programming:Display and update Scores|Display and update Scores]]
*[[Programming:Distorting the screen using register 2 of the CRTC (Horizontal Sync Position)|Distorting the screen using register 2 of the CRTC (Horizontal Sync Position)]]
*[[Programming:Fast plot|Fast plot]]
*[[Programming:Fast Sprites|Fast Sprites]] by [[User:Executioner|Executioner]]
*[[Programming:Fast Textoutput|Fast Textoutput]] by [[Prodatron]]
*[[Programming:Hardware scrolling|Hardware Scrolling]] by [[User:Executioner|Executioner]]
*[[Programming:Hardware scrolling 2|Hardware Scrolling 2]]
*[[Programming:Hardware scrolling the screen horizontally byte-by-byte using the CRTC|Hardware scrolling the screen horizontally byte-by-byte using the CRTC]]
*[[Programming:Hardware scrolling the screen using the CRTC|Hardware scrolling the screen using the CRTC]]
*[[Programming:Overscan|Overscan]]
*[[Programming:Plotting a sprite using character matrices|Plotting a sprite using character matrices]]
*[[Programming:Simple Raster Example 1|Simple Raster Example]]
*[[Programming:Simple Split Raster Example 1|Simple Split Raster Example]]
*[[Synchronising with the CRTC and display]]

== Interrupts ==
* [[Reliable use of interrupt mode 2 on the CPC]]

== Keyboard ==
*[[Programming:Keyboard scanning|Keyboard scanning]]

== Other routines ==
*[[Programming:An example boot sector (executed with rsx command CPM)|An example boot sector (executed with rsx command CPM)]]
*[[Programming:An example to define a RSX|An example to define a RSX]]
*[[Programming:Calling a RSX from outside of BASIC|Calling a RSX from outside of BASIC]]
*[[Programming:Dumping the data of BASIC or AMSDOS or an expansion rom|Dumping the data of BASIC or AMSDOS or an expansion rom]]
*[[Programming:Dumping the data of the lower rom|Dumping the data of the lower rom]]

== Sound ==
*[[Programming:Source code to show 0x0ff is always returned when reading PSG port B|Source code to show 0x0ff is always returned when reading PSG port B]]
*[[Programming:Source code to show it is possible to store data in PSG register 14 and 15 (port A and port B)|Source code to show it is possible to store data in PSG register 14 and 15 (port A and port B)]]
*[[Programming:Source code to show it is possible to store data in PSG register 14 and 15 even if the port has been set to input|Source code to show it is possible to store data in PSG register 14 and 15 even if the port has been set to input]]
*[[Programming:Source code to show that some registers always return 0 in some bits|Source code to show that some registers always return 0 in some bits]]
*[[Programming:Source code to show that when a port is read in output mode; the data read will be ANDed with the inputs to that port|Source code to show that when a port is read in output mode; the data read will be ANDed with the inputs to that port]]

== Cross Development ==
*[[Programming:Cross Development|Cross Development]]

User:Tlb

2010-04-14T19:34:53Z

Tlb: Created page with 'Hi, I'm a cpc user from germany since autumn 1984 (i was 7 years old then). i still own my first cpc464 and several ddi-1s and also some cpc6128, both with green and colour mon…'

Hi, I'm a cpc user from germany since autumn 1984 (i was 7 years old then).

i still own my first cpc464 and several ddi-1s and also some cpc6128, both with green and colour monitors. i was quite good at locomotive basic programming.

Programming:Unlocking a protected basic file

2010-04-14T19:27:37Z

Tlb: Created page with 'You can protect a basic program by saving it with save"filename",p You can still '''run"''' a protected basic file, but can't '''load"''' and list it. There is a way to unlo…'

You can protect a basic program by saving it with

save"filename",p

You can still '''run"''' a protected basic file, but can't '''load"''' and list it.

There is a way to unlock these basic files. This only works on a CPC 464 (real machine or emulator).

Type this:

poke &ac02,&90
poke &ac03,&c0
poke &ac01,&c3

then '''load"''' the protected basic file.
Done.

Now you can '''list''' this program.

Source Codes

2010-04-14T19:24:18Z

Tlb: /* File access */

[[Category:Programming]]
''This article contains source codes and programming examples. You may also have a look at''
* [[Programming software]]
* [[BIOS Functions]]
* [[Technical documentation]]s
* [[Locomotive BASIC]]
* [[Type Ins]]

== Assembler ==
*[[Z80_-_undocumented_opcodes|Z80 - undocumented opcodes]]
*[[Where to learn?]]

== Algorithms ==
*[[Programming:CPC OS floating point routines|CPC OS floating point routines]]
*[[Programming:CRC16|CRC16]]
*[[Programming:CRC32|CRC32]]
*[[Programming:Integer Division|Integer Division]]
*[[Programming:Integer Multiplication|Integer Multiplication]]
*[[Programming:Ultrafast Multiplication|Ultrafast Multiplication]] by [[Prodatron]]
*[[Programming:Fast Square Root|Fast Square Root]]
*[[Programming:Fast 16 bit Square Root|Fast 16 bit Square Root]] by [[User:Executioner|Executioner]]
*[[Programming:Filling memory with a byte|Filling memory with a byte]]
*[[Programming:Square Root|Square Root]]
*[[Programming:Precalculated square|Precalculated square]]
*[[Programming:Random Number Generator|Random Number Generator]]
*[[Programming:Quicksort|Quicksort]]
*[[Programming:Sin/Cos calculation|Sin/Cos calculation]]

== CP/M ==
*[[Programming:A simple 'Hello World' program for CP/M using BDOS|A simple 'Hello World' program for CP/M using BDOS]]
*[[Programming:A simple 'Hello World' program for CP/M using BIOS|A simple 'Hello World' program for CP/M using BIOS]]
*[[Programming:Executing firmware functions from within CP/M 2.1|Executing firmware functions from within CP/M 2.1]]
*[[Programming:Executing firmware functions from within CP/M 2.1 or CP/M plus|Executing firmware functions from within CP/M 2.1 or CP/M plus]]
*[[Programming:Executing firmware functions from within CP/M 2.1|Executing firmware functions from within CP/M 2.1]]
*[[Programming:Executing firmware functions from within CP/M plus|Executing firmware functions from within CP/M plus]]

== CPC Plus ==
*[[Amstrad CPC plus sprite format]]
*[[Programming:Convert CPC sprites to Plus hardware sprites|Convert CPC sprites to Plus hardware sprites]]
*[[Sprites Multiplexing]]
*[[Programming:CPC Plus Hardware Sprites|Hardware sprites]]
*[[Programming:CPC Plus Horizontal scroll|Horizontal scroll]]
*[[Programming:CPC Plus RLE Hardware Sprites|RLE hardware sprites]]
*[[Programming:CPC Plus Screen Splitting|Screen splitting]]
*[[Programming:CPC Plus Vertical scroll|Vertical scroll]]
*[[Operation of Z80 interrupt mode 0 in the CPC plus design]]
*[[Programming:Simple Raster Example 2 (uses CPC plus features)|Simple Raster Example 1 (uses CPC plus features)]]
*[[Programming:Simple Raster Example 3 (uses CPC plus features)|Simple Raster Example 2 (uses CPC plus features)]]
*[[Programming:Unlocking ASIC|Unlocking ASIC]]

== Devices ==
*[[Programming:CPC Booster|CPC Booster]]
*[[Programming:Digiblaster|Digiblaster]]
*[[Programming:Program to save the ROM of the Multiface 2|Program to save the ROM of the Multiface 2]]
*[[Programming:SYMBiFACE II|SYMBiFACE II]]

== File access ==
*[[Programming:An example to read a file byte-by-byte|An example to read a file byte-by-byte]]
*[[Programming:An example to write a file byte-by-byte|An example to write a file byte-by-byte]]
*[[Programming:A simple file copier using firmware functions (copies byte-by-byte)|A simple file copier using firmware functions (copies byte-by-byte)]]
*[[Programming:Loading a file|Loading a file]]
*[[Programming:Saving a file|Saving a file]]
*[[Programming:Unlocking a protected basic file|Unlocking a protected basic file]]

== Floppy disk ==
*[[Programming:A simple disc copier using BDOS functions|A simple disc copier using BDOS functions]]
*[[Programming:A simple disc formatter using BDOS functions|A simple disc formatter using BDOS functions]]
*[[Programming:An example loader|An example loader]]
*[[Programming:Catalog a disc and retrieve a directory|Catalog a disc and retrieve a directory]]
*[[Programming:Detecting an Amstrad or Vortex disc controler|Detecting an Amstrad or Vortex disc controler]]
*[[Programming:Formatting a track on a disc|Formatting a track on a disc]]
*[[Programming:Reading a sector from a disc|Reading a sector from a disc]]
*[[Programming:Reading and writing the boot sector of a SYSTEM/VENDOR disc|Reading and writing the boot sector of a SYSTEM/VENDOR disc]]
*[[Programming:Writing a sector to disc|Writing a sector to disc]]

== Graphics ==
*[[Programming:Display a 8-bit number in binary|Display a 8-bit number in binary]]
*[[Programming:Display a 8-bit number in hex|Display a 8-bit number in hex]]
*[[Programming:Display a byte as a 3-digit decimal number|Display a byte as a 3-digit decimal number]]
*[[Programming:Display and update Scores|Display and update Scores]]
*[[Programming:Distorting the screen using register 2 of the CRTC (Horizontal Sync Position)|Distorting the screen using register 2 of the CRTC (Horizontal Sync Position)]]
*[[Programming:Fast plot|Fast plot]]
*[[Programming:Fast Sprites|Fast Sprites]] by [[User:Executioner|Executioner]]
*[[Programming:Fast Textoutput|Fast Textoutput]] by [[Prodatron]]
*[[Programming:Hardware scrolling|Hardware Scrolling]] by [[User:Executioner|Executioner]]
*[[Programming:Hardware scrolling 2|Hardware Scrolling 2]]
*[[Programming:Hardware scrolling the screen horizontally byte-by-byte using the CRTC|Hardware scrolling the screen horizontally byte-by-byte using the CRTC]]
*[[Programming:Hardware scrolling the screen using the CRTC|Hardware scrolling the screen using the CRTC]]
*[[Programming:Overscan|Overscan]]
*[[Programming:Plotting a sprite using character matrices|Plotting a sprite using character matrices]]
*[[Programming:Simple Raster Example 1|Simple Raster Example]]
*[[Programming:Simple Split Raster Example 1|Simple Split Raster Example]]
*[[Synchronising with the CRTC and display]]

== Interrupts ==
* [[Reliable use of interrupt mode 2 on the CPC]]

== Keyboard ==
*[[Programming:Keyboard scanning|Keyboard scanning]]

== Other routines ==
*[[Programming:An example boot sector (executed with rsx command CPM)|An example boot sector (executed with rsx command CPM)]]
*[[Programming:An example to define a RSX|An example to define a RSX]]
*[[Programming:Calling a RSX from outside of BASIC|Calling a RSX from outside of BASIC]]
*[[Programming:Dumping the data of BASIC or AMSDOS or an expansion rom|Dumping the data of BASIC or AMSDOS or an expansion rom]]
*[[Programming:Dumping the data of the lower rom|Dumping the data of the lower rom]]

== Sound ==
*[[Programming:Source code to show 0x0ff is always returned when reading PSG port B|Source code to show 0x0ff is always returned when reading PSG port B]]
*[[Programming:Source code to show it is possible to store data in PSG register 14 and 15 (port A and port B)|Source code to show it is possible to store data in PSG register 14 and 15 (port A and port B)]]
*[[Programming:Source code to show it is possible to store data in PSG register 14 and 15 even if the port has been set to input|Source code to show it is possible to store data in PSG register 14 and 15 even if the port has been set to input]]
*[[Programming:Source code to show that some registers always return 0 in some bits|Source code to show that some registers always return 0 in some bits]]
*[[Programming:Source code to show that when a port is read in output mode; the data read will be ANDed with the inputs to that port|Source code to show that when a port is read in output mode; the data read will be ANDed with the inputs to that port]]

== Cross Development ==
*[[Programming:Cross Development|Cross Development]]