UserDoc:How AmigaOS Works - Revision history

Brian Deneen: /* Removing the JIT Emulator */ Removed excess "the" occurrences and changed punctuation for smoother reading. Please see "Show Changes" page.

2023-10-03T15:51:28Z

Removing the JIT Emulator: Removed excess "the" occurrences and changed punctuation for smoother reading. Please see "Show Changes" page.

← Older revision		Revision as of 15:51, 3 October 2023
Line 330:		Line 330:
	== Removing the JIT Emulator ==		== Removing the JIT Emulator ==

	Using ~~the~~ dynamic translation requires a lot more memory than ~~the~~ interpretive emulation. The translated code needs to be stored somewhere, not to mention the data collection tables.		Using dynamic translation requires a lot more memory than interpretive emulation. The translated code needs to be stored somewhere, not to mention the data collection tables.

	If speed is not as important as the memory consumption of the system, ~~then~~ the JIT emulator can be removed, leaving the job to the interpretive emulator.		If speed is not as important as the memory consumption of the system, the JIT emulator can be removed, leaving the job to the interpretive emulator.

	Thanks to the modular design of AmigaOS kickstart, all you need to do is edit the "Sys:Kickstart/Kicklayout" file, ~~simply~~ put a semicolon (;) at the beginning of the module line of Petunia.library.kmod. After ~~rebooting~~ ~~the~~ system ~~from cold~~, the JIT emulator will not be reloaded. Make sure that you alter the appropriate configuration in the Kicklayout file, ~~there~~ may be several alternative configurations, with different names ~~like~~ "DefaultJIT", or "DefaultNoJIT".		Thanks to the modular design of AmigaOS kickstart, all you need to do is edit the "Sys:Kickstart/Kicklayout" file. Simply put a semicolon (;) at the beginning of the module line "Petunia.library.kmod". After executing a "cold" system reboot, the JIT emulator will not be reloaded. Make sure that you alter the appropriate configuration in the Kicklayout file. There may be several alternative configurations with different names, such as "DefaultJIT" or "DefaultNoJIT".

	== Configuring the Emulators ==		== Configuring the Emulators ==

Brian Deneen: /* Two 680x0 Emulators */ Various reconstruction of sentences for clarity. Please see the "Show changes" page

2023-10-03T15:41:43Z

Two 680x0 Emulators: Various reconstruction of sentences for clarity. Please see the "Show changes" page

← Older revision		Revision as of 15:41, 3 October 2023
Line 310:		Line 310:
	== Two 680x0 Emulators ==		== Two 680x0 Emulators ==

	In version 4.0 of AmigaOS, two different emulators were implemented; ~~one~~ is the successor of BlackBox emulation, it is an interpretive emulator, ~~thus~~ ~~the~~ emulation speed ~~is mediocre~~. On the other hand it has a very low "reaction time", and is ideal for time critical parts, such as interrupts.		In version 4.0 of AmigaOS, two different emulators were implemented. One is the successor of BlackBox emulation. It is an interpretive emulator with mediocre emulation speed. On the other hand, it has a very low "reaction time" and is ideal for time critical parts, such as interrupts.

	The other is Petunia, the "JIT emulator". A fast, but less compatible way of emulation of the legacy Motorola processors. It is intended mainly for emulating applications~~, and therefore,~~ ~~when~~ execution of the application leaves the bounds of the application's code segment, emulation falls back to the interpretive method, where it does its job and returns to the JIT emulation again.		The other is Petunia, the "JIT emulator", a fast but less compatible way of emulation of the legacy Motorola processors. It is intended mainly for emulating applications. When execution of the application leaves the bounds of the application's code segment, emulation falls back to the interpretive method, where it does its job and returns to the JIT emulation again.

	Dynamic recompilation (also called just-in-time compilation or simply JIT compilation) is a technique of translating foreign processor machine code to native machine code, "on the fly".		Dynamic recompilation (also called just-in-time compilation or simply JIT compilation) is a technique of translating foreign processor machine code to native machine code "on the fly".

	This technique is common nowadays~~, commonly applied~~ in JAVA virtual machines, ~~and~~ it is also used with success in several emulators. In dynamic recompilation there is the possibility of runtime optimization of the emulated code by collecting statistics of the execution process. Therefore (theoretically) the final executed code can be even faster than the original code on its original processor.		This technique is common nowadays in JAVA virtual machines. It is also used with success in several emulators. In dynamic recompilation, there is the possibility of runtime optimization of the emulated code by collecting statistics of the execution process. Therefore (theoretically) the final executed code can be even faster than the original code on its original processor.

	== Features ==		== Features ==

Brian Deneen: /* How to make a Bootable USB Memory Stick for AmigaOS 4.1 */ 20.3. Added "from" after "read" to maintain parallel construction.

2023-10-03T15:26:31Z

How to make a Bootable USB Memory Stick for AmigaOS 4.1: 20.3. Added "from" after "read" to maintain parallel construction.

← Older revision		Revision as of 15:26, 3 October 2023
Line 410:		Line 410:
	## Select the file system that you are going to use by selecting the pull down menu under "Filesystem chooser".		## Select the file system that you are going to use by selecting the pull down menu under "Filesystem chooser".
	## Only filesystems SFS/00 or SFS/02 will work for a bootable device.		## Only filesystems SFS/00 or SFS/02 will work for a bootable device.
	## The option that gives the most flexibility at the moment is SFS/00 as a USB stick in this format can be read and written to using another compatible system in the event that you need to make modifications after it is created without a booting AmigaOS 4.1 machine.		## The option that gives the most flexibility at the moment is SFS/00 as a USB stick in this format can be read from and written to using another compatible system in the event that you need to make modifications after it is created without a booting AmigaOS 4.1 machine.
	## Next select Blocksize from the "Blocksize" pull down menu. 512 is the correct size to use.		## Next select Blocksize from the "Blocksize" pull down menu. 512 is the correct size to use.
	## Now Select "Ok-accept changes".		## Now Select "Ok-accept changes".

Tony Wyatt at 02:47, 2 September 2017

2017-09-02T02:47:58Z

← Older revision		Revision as of 02:47, 2 September 2017
Line 356:		Line 356:
	* [[File:Uboot.jpg\|200px]]		* [[File:Uboot.jpg\|200px]]
	The BIOS ([[UserDoc:BIOS\|Uboot]] or [[UserDoc:BIOS\|CFE]]) of the computer initialises the hardware: graphic card, USB ports... At this point, the monitor wakes up and the first information is displayed. This shows if hardware is correctly recognised. As an example you can see if a hard drive is correctly connected into the machine and your BIOS is correctly set up to make this drive useable.		The BIOS ([[UserDoc:BIOS\|Uboot]] or [[UserDoc:BIOS\|CFE]]) of the computer initialises the hardware: graphic card, USB ports... At this point, the monitor wakes up and the first information is displayed. This shows if hardware is correctly recognised. As an example you can see if a hard drive is correctly connected into the machine and your BIOS is correctly set up to make this drive useable.
	* Depending on ~~how~~ ~~you~~ ~~set up~~ the BIOS it will look on the harddisk to find the Second Level Booter (SLB) or will execute the AmigaBoot program from the on-board NVRAM. Whereas the BIOS does not know about AmigaOS disk structure, the SLB/AmigaBoot ~~will be able to~~ ''understand'' the AmigaOS partitions and ~~files~~. In other words, it is the link between the BIOS and the rest of the boot procedure. Its goal is also to give you the ability to start several configurations present on the same drive.		* Depending on the machine type, the BIOS will look on the harddisk to find the Second Level Booter (SLB) or AmigaBoot, or will execute the AmigaBoot program from the on-board NVRAM. Whereas the BIOS does not know about AmigaOS disk structure, the SLB/AmigaBoot can ''understand'' the AmigaOS partitions and file systems. In other words, it is the link between the BIOS and the rest of the boot procedure. Its goal is also to give you the ability to start several configurations present on the same drive.
	* [[File:SLB.png\|200px]]		* [[File:SLB.png\|200px]]
	SLB/AmigaBoot analyses all Amiga partitions on the system disk. It reads each ~~[[UserDoc:kickstart_configuration\|~~system configuration]] it finds on the partition. It ~~will~~ ~~show~~ all ~~available configurations~~ for the user to select one to load.		SLB/AmigaBoot analyses all Amiga partitions on the system disk. It reads each system configuration it finds on the partition and displays them all for the user to select one to load. AmigaBoot (not SLB) also displays configurations from Kickstart/Kicklayout files on every "bootable" partition.
	The user can define many different kickstart configurations to choose from. Also both AmigaOS and Linux can be selected for boot.		The user can [[UserDoc:How_AmigaOS_Works#Control_of_the_Kickstart\|define]] many different kickstart configurations to choose from. Also both AmigaOS and Linux can be selected for boot.
	* [[File:Kmods loading.png\|200px]]		* [[File:Kmods loading.png\|200px]]
	SLB/AmigaBoot loads the kickstart files of the selected configuration and executes the '''Loader''' module		SLB/AmigaBoot loads the kickstart files of the selected configuration and executes the '''Loader''' module

Tony Wyatt at 02:22, 2 September 2017

2017-09-02T02:22:15Z

← Older revision		Revision as of 02:22, 2 September 2017
Line 350:		Line 350:
	= AmigaOS boot procedure =		= AmigaOS boot procedure =

	Classic Amigas with PowerPC accelerators, the original AmigaOne SE/XE and the Sam series of Amigas all use the Second Level Booter (SLB) to read their Kickstart modules from the system volume. The newer A-Eon machines (X1000, X5000, A1222) all use a loader called AmigaBoot, ~~which~~ is stored in the on-board ~~NVRAM or~~ CF card. The process of loading the kickstart modules is the same in all cases.		Classic Amigas with PowerPC accelerators, the original AmigaOne SE/XE and the Sam series of Amigas all use the Second Level Booter (SLB) to read their Kickstart modules from the system volume. The newer A-Eon machines (X1000, X5000, A1222) all use a loader called AmigaBoot. In the X1000, AmigaBoot must be read from an FFS partition, while in the later machines, it is stored in the on-board CF card. The process of loading the kickstart modules is the same in all cases.

	Basically a computer with AmigaOS does the following when the power button is pushed:		Basically a computer with AmigaOS does the following when the power button is pushed:

Tony Wyatt at 02:18, 2 September 2017

2017-09-02T02:18:15Z

Tony Wyatt at 02:01, 2 September 2017

2017-09-02T02:01:11Z

← Older revision		Revision as of 02:01, 2 September 2017
Line 221:		Line 221:
	You can edit the Kicklayout file using Notepad or any other ASCII editor. You are strongly advised to leave the original configuration unchanged (as a fall-back) and to add new configurations at the end of the file, each with its own label. That way you can still recover if you make a mistake while editing.		You can edit the Kicklayout file using Notepad or any other ASCII editor. You are strongly advised to leave the original configuration unchanged (as a fall-back) and to add new configurations at the end of the file, each with its own label. That way you can still recover if you make a mistake while editing.

			<nowiki>; Configuration name
	[[File: kicklayout.png\|frame\|right\|Portion of a typical Kicklayout]]
			LABEL MainSystem
			; Exec name
			EXEC Kickstart/loader.of
			;
			; PPC native modules
			;
			MODULE Kickstart/kernel
			;
			MODULE Kickstart/FastFileSystem
			MODULE Kickstart/CDFileSystem
			MODULE Kickstart/NGFileSystem
			;
			(etc)</nowiki>


	Note that lines that start with a semicolon (";") are treated as comments and are ignored. Each configuration must start with a "LABEL" keyword and should be separated from the previous configuration by a blank line. The blank line signifies "Stop loading here".		Note that lines that start with a semicolon (";") are treated as comments and are ignored. Each configuration must start with a "LABEL" keyword and should be separated from the previous configuration by a blank line. The blank line signifies "Stop loading here".

Tony Wyatt at 01:49, 2 September 2017

2017-09-02T01:49:08Z

← Older revision		Revision as of 01:49, 2 September 2017
Line 246:		Line 246:
	[[File:Workbench_directory_listing.png\|frame\|right\|List of directories and files present at the root of any AmigaOS system]]		[[File:Workbench_directory_listing.png\|frame\|right\|List of directories and files present at the root of any AmigaOS system]]

	Beside the kickstart modules, AmigaOS uses many different components that can be loaded only when ~~used~~. These files are stored in different directories in the system volume.		Beside the kickstart modules, AmigaOS uses many different components that can be loaded only when needed. These files are stored in different directories in the system volume.
	~~Here is described a~~ default AmigaOS installation.		A default AmigaOS installation looks like this:

	* C		* C
Line 254:		Line 254:
	contains different object elements easy to be used in any program: gadgets, requesters, graphic table, windows...		contains different object elements easy to be used in any program: gadgets, requesters, graphic table, windows...
	* Devs		* Devs
	contains ~~definition~~ for '''Dev'''ices		contains definitions for '''Dev'''ices
	* Emulation		* Emulation
	contains files used for the 68k emulation (though E-UAE)		contains files used for the 68k emulation (though E-UAE)
Line 260:		Line 260:
	contains various systems fonts		contains various systems fonts
	* Internet		* Internet
	contains a ~~dialer~~ to ~~connect to Internet~~		contains Internet-related files and configurations
	* Kickstart		* Kickstart
	contains the kickstart modules		contains the kickstart modules
Line 266:		Line 266:
	contains hand'''l'''ers and filesystems		contains hand'''l'''ers and filesystems
	* Libs		* Libs
	contains dynamic '''~~Libr~~'''~~airies~~ of functions		contains dynamic '''Lib'''rairies of functions
	* Locale		* Locale
	contains all files used to ~~localise~~ the system (catalogs, keymaps...)		contains all files used to customise the system for your locality (catalogs, keymaps...)
	* MUI		* MUI
	contains the ~~needed~~ files for programs that use the MUI third party graphic interface		contains the files needed for programs that use the MUI third party graphic interface
	* [[Prefs]]		* [[Prefs]]
	contains the preference programs used to customise AmigaOS		contains the preference programs used to customise AmigaOS
	* S		* S
	contains the '''S'''cripts		contains the system's '''S'''cripts
	* SObjs		* SObjs
	contains .so shared object library files		contains .so shared object library files
	* Storage		* Storage
	contains other optional files		contains other optional files, not currently used
	* System		* System
	contains some programs used by the system itself (i.e. you don't need to run them yourself) or low-level programs like disk tools		contains some programs used by the system itself (i.e. you don't need to run them yourself) or low-level programs like disk tools

Tony Wyatt at 01:43, 2 September 2017

2017-09-02T01:43:27Z

Show changes

Tony Wyatt at 01:13, 2 September 2017

2017-09-02T01:13:11Z

← Older revision		Revision as of 01:13, 2 September 2017
Line 208:		Line 208:
	* xena.resource.kmod - provides access to the Xena chip on the AmigaOne X1000		* xena.resource.kmod - provides access to the Xena chip on the AmigaOne X1000

	=== Misc modules ===		==== Misc modules ====

	* petunia.library.kmod - this module contains the Just-In-Time emulator that allows AmigaOS to run programs made for the Motorola 68k processor		* petunia.library.kmod - this module contains the Just-In-Time emulator that allows AmigaOS to run programs made for the Motorola 68k processor

	=== Control of the Kickstart ===		== Control of the Kickstart ==

	The Kickstart/ drawer contains an ASCII file called "Kicklayout". This file lists all the modules that must be loaded from the system volume during the boot process. It is read by the boot loaders "SLB" or "amigaboot".		The Kickstart/ drawer contains an ASCII file called "Kicklayout". This file lists all the modules that must be loaded from the system volume during the boot process. It is read by the boot loaders "SLB" or "amigaboot".

	The Kicklayout file consists of a number of configurations, each of which describes a set of Kickstart modules. Each configuration has a label and the various configurations are listed by label on the boot screen. The user may elect to allow the default configuration or to select any one of the ~~available~~ configurations. Often a developer may have several configurations in his/her Kicklayout file, some of which may be experimental, while the default is a "known good" configuration to which (s)he can fall back.		The Kicklayout file consists of a number of configurations, each of which describes a set of Kickstart modules. Each configuration has a label and the various configurations are listed by label on the boot screen. The user may elect to allow the default configuration or to select any one of the other configurations. Often a developer may have several configurations in his/her Kicklayout file, some of which may be experimental, while the default is a "known good" configuration to which (s)he can fall back.

	You can edit the Kicklayout file using Notepad or any other ~~ASCIII~~ editor. You are strongly advised to leave the original configuration unchanged (as a fall-back) and to add new configurations at the end of the file, each with its own label. That way you can still recover if you make a mistake while editing.		You can edit the Kicklayout file using Notepad or any other ASCII editor. You are strongly advised to leave the original configuration unchanged (as a fall-back) and to add new configurations at the end of the file, each with its own label. That way you can still recover if you make a mistake while editing.

			[[File: kicklayout.png\|frame\|right\|Portion of a typical Kicklayout]]
	The individual configurations are headed by lines like these:
	; Configuration name
	LABEL DefaultSystem
	; Exec name
	EXEC Kickstart/loader.of
	;
	; PPC native modules
	;
	MODULE Kickstart/kernel
	(etc)

	Note that lines that start with a semicolon (";") are treated as comments and are ignored. Each configuration must start with a "LABEL" and should be separated from the previous configuration by a blank line.		Note that lines that start with a semicolon (";") are treated as comments and are ignored. Each configuration must start with a "LABEL" keyword and should be separated from the previous configuration by a blank line. The blank line signifies "Stop loading here".

	Each module to be loaded is defined by the "MODULE" keyword, followed by the path and file name. You can use any path '''on the system volume''', so you could have two or more drawers containing Kickstart modules and address them independently if you so wished. You can not refer to modules on other volumes, since they have not been mounted by DOS (which does not exist yet) and only the system volume is available at this early stage.		Each module to be loaded is defined by the "MODULE" keyword, followed by the path and file name. You can use any path '''on the system volume''', so you could have two or more drawers containing Kickstart modules and address them independently if you so wished. You can not refer to modules on other volumes, since they have not been mounted by DOS (which does not exist yet) and only the system volume is available at this early stage.
Line 246:		Line 237:

	[Note that nvsetvar may be inhibited from writing to the NVRAM on some systems, in which case you will have to use U-Boot or CFE to set the variable]		[Note that nvsetvar may be inhibited from writing to the NVRAM on some systems, in which case you will have to use U-Boot or CFE to set the variable]

			If you do not specify a default configuration with the "boot_config" variable, the boot loader will default to the first configuration in the Kicklayout.


	== System components ==		== System components ==

← Older revision		Revision as of 02:18, 2 September 2017
Line 338:		Line 338:
	== Configuring the Emulators ==		== Configuring the Emulators ==

	Petunia cooperates with a so called "black list". By default Petunia emulates every 680x0 program or library that is loaded by DOS.library/LoadSeg function, but if an executable or library shows incompatibilities with Petunia, then it can be explicitly inhibited from the dynamic recompilation by specifying it in a list ~~file~~.		Petunia cooperates with a so called "black list". By default, Petunia emulates every 680x0 program or library that is loaded by DOS.library/LoadSeg function, but if an executable or library shows incompatibilities with Petunia, then it can be explicitly inhibited from the dynamic recompilation by specifying it in a list.

	If an executable needs to be added to the list, then it can be done by extending the file "DEVS:applications.dos" with the '''Compatibility''' preferences program from the Prefs drawer of the system. Adding a program name to the list and checking it will prevent Petunia from emulating that program, and it will be interpreted instead by the built-in interpreter.		If an executable needs to be added to the list, then it can be done by extending the file "DEVS:applications.dos" with the '''Compatibility''' preferences program from the Prefs drawer of the system. Adding a program name to the list and checking it will prevent Petunia from emulating that program, and it will be interpreted instead by the built-in interpreter.
Line 346:		Line 346:
	Please note: some programs consist of multiple executables (shared libraries, plugins). If you want to fully disable the translation of such programs, then every part must be added to the list.		Please note: some programs consist of multiple executables (shared libraries, plugins). If you want to fully disable the translation of such programs, then every part must be added to the list.

	For example to disable UnArc fully, you would have to add all files from libs:xad and also xadmaster.library ~~to the list~~.		For example to disable UnArc fully, you would have to add to the list all files from libs:xad and also xadmaster.library.

	= AmigaOS boot procedure =		= AmigaOS boot procedure =

			Classic Amigas with PowerPC accelerators, the original AmigaOne SE/XE and the Sam series of Amigas all use the Second Level Booter (SLB) to read their Kickstart modules from the system volume. The newer A-Eon machines (X1000, X5000, A1222) all use a loader called AmigaBoot, which is stored in the on-board NVRAM or CF card. The process of loading the kickstart modules is the same in all cases.

	Basically a computer with AmigaOS does the following when the power button is pushed:		Basically a computer with AmigaOS does the following when the power button is pushed:

	* [[File:Uboot.jpg\|200px]]		* [[File:Uboot.jpg\|200px]]
	~~the~~ BIOS ([[UserDoc:BIOS\|Uboot]] or [[UserDoc:BIOS\|CFE]]) of the computer initialises the hardware: graphic card, USB ports... At this point, the monitor wakes up and the first information ~~are~~ displayed. This ~~allows to see~~ if hardware is correctly recognised. As an example you can see if a hard drive is correctly connected into the machine and your BIOS is correctly ~~setup~~ to make this drive useable.		The BIOS ([[UserDoc:BIOS\|Uboot]] or [[UserDoc:BIOS\|CFE]]) of the computer initialises the hardware: graphic card, USB ports... At this point, the monitor wakes up and the first information is displayed. This shows if hardware is correctly recognised. As an example you can see if a hard drive is correctly connected into the machine and your BIOS is correctly set up to make this drive useable.
	* ~~depending~~ on how you ~~setup~~ the BIOS it will look on the harddisk to find the Second Level Booter (SLB). ~~This~~ ~~program~~ ~~is stored on~~ the ~~first~~ ~~sectors~~ of the ~~disk~~. Whereas the BIOS does not know about AmigaOS disk structure, the SLB will be able to ''understand'' the AmigaOS partitions and files. In other words, it is the link between the BIOS and the rest of the boot procedure. Its goal is also to give you the ability to start several configurations present on the same drive.		* Depending on how you set up the BIOS it will look on the harddisk to find the Second Level Booter (SLB) or will execute the AmigaBoot program from the on-board NVRAM. Whereas the BIOS does not know about AmigaOS disk structure, the SLB/AmigaBoot will be able to ''understand'' the AmigaOS partitions and files. In other words, it is the link between the BIOS and the rest of the boot procedure. Its goal is also to give you the ability to start several configurations present on the same drive.
	* [[File:SLB.png\|200px]]		* [[File:SLB.png\|200px]]
	~~the~~ SLB ~~will~~ analyses all Amiga partitions on the disk ~~it is installed on~~. It ~~will read~~ each [[UserDoc:kickstart_configuration\|system configuration]] it finds on the ~~partitions~~. It will show all available configurations for the user to select one to load.		SLB/AmigaBoot analyses all Amiga partitions on the system disk. It reads each [[UserDoc:kickstart_configuration\|system configuration]] it finds on the partition. It will show all available configurations for the user to select one to load.
	The user can define many different kickstart configurations to choose from. Also both AmigaOS and Linux can be selected for boot.		The user can define many different kickstart configurations to choose from. Also both AmigaOS and Linux can be selected for boot.
	* [[File:Kmods loading.png\|200px]]		* [[File:Kmods loading.png\|200px]]
	~~the~~ SLB loads the kickstart files of the selected configuration and executes the '''Loader''' module		SLB/AmigaBoot loads the kickstart files of the selected configuration and executes the '''Loader''' module
	* '''Loader''' executes the kickstart modules (Exec, devices, libraries...)		* '''Loader''' executes the kickstart modules (Exec, devices, libraries...)
	* AmigaOS becomes alive displaying the AmigaOS boot picture on the monitor		* AmigaOS becomes alive displaying the AmigaOS boot picture on the monitor
	* ~~the~~ AmigaDOS library executes the [[UserDoc:System_Scripts#startup-sequence\|startup-sequence]] script found on the system volume		* The AmigaDOS library executes the [[UserDoc:System_Scripts#startup-sequence\|startup-sequence]] script found on the system volume
	* ~~the~~ Startup-sequence will be executed and all commands it contains are executed. It means that starting from here the boot procedure is easy to follow and understand.		* The Startup-sequence will be executed and all commands it contains are executed. It means that starting from here the boot procedure is easy to follow and understand.
	* ~~the~~ Workbench is started		* The Workbench is started

	At this point the user can use his/her computer.		At this point the user can use his/her computer.