AMC-OS Loader - Revision history

Kindman at 15:28, 18 April 2020

2020-04-18T15:28:37Z

← Older revision		Revision as of 17:28, 18 April 2020
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	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode
	* [[AMC-OS Loader Memory management\|Check for EBDA and initialize first MB of memory to allow memory allocation]]		* [[AMC-OS Loader Memory management\|Check for EBDA and initialize first MB of memory to allow memory allocation]]
	* [[Memory ~~identification~~\|Ask BIOS information on the available RAM in the system]]		* [[Memory initialization\|Ask BIOS information on the available RAM in the system]]
	* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency
	* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot		* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot

Kindman at 15:19, 13 April 2020

2020-04-13T15:19:17Z

← Older revision		Revision as of 17:19, 13 April 2020
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	* Wait for options (typically F1 for debugging purposes if compiled with DEBUG support)		* Wait for options (typically F1 for debugging purposes if compiled with DEBUG support)
	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode
	* ~~Check for EBDA and~~ [[AMC-OS Loader Memory management\|initialize first MB of memory to allow memory allocation]]		* [[AMC-OS Loader Memory management\|Check for EBDA and initialize first MB of memory to allow memory allocation]]
	* Ask BIOS information on the available RAM in the system.		* [[Memory identification\|Ask BIOS information on the available RAM in the system]]
	* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency
	* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot		* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot

Kindman at 15:17, 13 April 2020

2020-04-13T15:17:59Z

← Older revision		Revision as of 17:17, 13 April 2020
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	* Wait for options (typically F1 for debugging purposes if compiled with DEBUG support)		* Wait for options (typically F1 for debugging purposes if compiled with DEBUG support)
	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode
	* Check for EBDA and initialize first MB of memory to allow memory allocation ~~: [[AMC-OS Loader Memory management~~]]		* Check for EBDA and [[AMC-OS Loader Memory management\|initialize first MB of memory to allow memory allocation]]
	* Ask BIOS information on the available RAM in the system.		* Ask BIOS information on the available RAM in the system.
	* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency

Kindman at 14:46, 13 April 2020

2020-04-13T14:46:32Z

← Older revision		Revision as of 16:46, 13 April 2020
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	[[image:Amcos_loader.png\|right\|thumb\|250px\|AMC-OS Loader splash screen]]		[[image:Amcos_loader.png\|right\|thumb\|250px\|AMC-OS Loader splash screen]]
	AMC-OS Loader follow this procedure :		AMC-OS Loader follow this procedure :
			* Wait for options (typically F1 for debugging purposes if compiled with DEBUG support)
	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode
	* Ask BIOS information on the available RAM in the system ~~and initialize low memory (<640KB) for allocation~~.		* Check for EBDA and initialize first MB of memory to allow memory allocation : [[AMC-OS Loader Memory management]]
			* Ask BIOS information on the available RAM in the system.
	* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency
	* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot		* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot
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	Both files are loaded by the [[Boot process#The Boot Loader\|boot sector]].		Both files are loaded by the [[Boot process#The Boot Loader\|boot sector]].

			==16-bit code and V86==
			AMC-OS Loader stays in memory to allow 16-bit code to be executed from Kernel in V86 mode, typically to call INT 10H (video)

Kindman: /* Process */

2017-05-16T10:52:52Z

Process

← Older revision		Revision as of 12:52, 16 May 2017
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	AMC-OS Loader follow this procedure :		AMC-OS Loader follow this procedure :
	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode
	* ~~Load~~ and ~~compare the disk FATs, converts them to FAT16 for simpler management~~ (~~for FAT12 floppy disks~~)		* Ask BIOS information on the available RAM in the system and initialize low memory (<640KB) for allocation.
	* Locate the <tt>MODULES</tt> directory containing all kernel files required for ~~boot~~
	* Load all kernel files in memory using the contents of the <tt>[[AMCOS.~~MOD]]</tt> file~~
	* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency
			* Check if we start from a MBR (removeable media) or a VBR and locate volume to boot
			* Identify the volume type (FAT12, FAT16...) and initialize according filesystem driver.
			* Locate and load the required kernel files
	* Identify the video graphics card, check VESA support to get best text resolution during kernel initialization		* Identify the video graphics card, check VESA support to get best text resolution during kernel initialization
	* Prepare the CPU for protected mode (GDT and system descriptors)		* Prepare the CPU for protected mode (GDT and system descriptors)

Kindman: /* Introduction */

2017-05-16T10:49:43Z

Introduction

← Older revision		Revision as of 12:49, 16 May 2017
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	==Introduction==		==Introduction==

	AMC-OS Loader gives us much more flexibility in [[Boot process\|boot process]], as we no longer have the limitation of 512 bytes of code. However, the CPU is still running in real mode, ~~causing some difficulties~~ to ~~load more than 640KB (not enough available memory)~~		AMC-OS Loader is a module part of the [[Boot process\|boot process]]. Its task is to locate the kernel in the booting volume, load it in memory and prepare all the necessary structures to start it.

			AMC-OS Loader gives us much more flexibility in [[Boot process\|boot process]], as we no longer have the limitation of 512 bytes of code. However, the CPU is still running in real mode, implying limitations in the size of structures and files we have to manipulate.

	==Process==		==Process==

Kindman at 18:19, 15 August 2012

2012-08-15T18:19:56Z

← Older revision		Revision as of 20:19, 15 August 2012
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	* Locate the <tt>MODULES</tt> directory containing all kernel files required for boot		* Locate the <tt>MODULES</tt> directory containing all kernel files required for boot
	* Load all kernel files in memory using the contents of the <tt>[[AMCOS.MOD]]</tt> file		* Load all kernel files in memory using the contents of the <tt>[[AMCOS.MOD]]</tt> file
	* Precisely identify the CPU using either the CPUID instruction or a CPU reset, and calculates its running frequency		* Precisely [[Identifying CPU\|identify the CPU]] using either the CPUID instruction or a CPU reset, and calculates its running frequency
	* Identify the video graphics card, check VESA support to get best text resolution during kernel initialization		* Identify the video graphics card, check VESA support to get best text resolution during kernel initialization
	* Prepare the CPU for protected mode (GDT and system descriptors)		* Prepare the CPU for protected mode (GDT and system descriptors)

Kindman: Added splash screen

2012-08-15T17:34:37Z

Added splash screen

← Older revision		Revision as of 19:34, 15 August 2012
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	==Process==		==Process==
			[[image:Amcos_loader.png\|right\|thumb\|250px\|AMC-OS Loader splash screen]]
	AMC-OS Loader follow this procedure :		AMC-OS Loader follow this procedure :
	* System check : Check that we have a 386+ running in real-mode		* System check : Check that we have a 386+ running in real-mode

Kindman at 16:41, 12 August 2012

2012-08-12T16:41:08Z

← Older revision		Revision as of 18:41, 12 August 2012
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	==Files==		==Files==
	AMC-OS Loader is composed of two files :		AMC-OS Loader is composed of two files :
	* <tt>AMCOSLDR.SYS</tt> contains code		* <tt>AMCOSLDR.SYS</tt> contains raw code of AMC-OS Loader (no header nor relocation).
	* <tt>AMCOSLDR.IMG</tt> is a picture of AMC-OS Logo displayed during AMC-OS Loader execution		* <tt>AMCOSLDR.IMG</tt> is a picture of AMC-OS Logo displayed during AMC-OS Loader execution.

	Both files are loaded by the [[Boot process#The Boot Loader\|boot sector]].		Both files are loaded by the [[Boot process#The Boot Loader\|boot sector]].

Kindman: Added AMC-OS Loader files section

2012-08-12T16:39:48Z

Added AMC-OS Loader files section

← Older revision		Revision as of 18:39, 12 August 2012
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	* Do a first switch to protected mode to decode kernel AMCX file and relocate it in memory		* Do a first switch to protected mode to decode kernel AMCX file and relocate it in memory
	* Do a second switch to protected mode to start kernel		* Do a second switch to protected mode to start kernel

			==Files==
			AMC-OS Loader is composed of two files :
			* <tt>AMCOSLDR.SYS</tt> contains code
			* <tt>AMCOSLDR.IMG</tt> is a picture of AMC-OS Logo displayed during AMC-OS Loader execution

			Both files are loaded by the [[Boot process#The Boot Loader\|boot sector]].