OS2 World Community Forum

OS/2, eCS & ArcaOS - Technical => Setup & Installation => Topic started by: Martin Iturbide on December 08, 2021, 08:56:27 pm

Title: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 08, 2021, 08:56:27 pm
Hi

ArcaOS 5.0.7 is out and I was creating my Vanilla VirtualBox VM with a fresh install.
I have a Windows 10 host with VirtualBox 6.1.30 and I want to validate some questions that I have.

1) Video: Should I select Panorama on the install, or it does not make a different with the default gengrad for VirtualBox?
2) RAM:  I'm putting 4096 MB of RAM. I don't know if there any comments about it.
3) Audio: I selected ICH AC97, I guess it has a similar performance as Intel HD and SB with Uniaud.
4) Network: The emulated Intel Pro and PCNet adapter works, but I'm not sure if the newer Intel drivers has a better performance. Should I go with Intel?
5) Display: Video Memory: Does it makes any different putting increasing the memory (like to 128MB) ?
6) Storage: Is there any performance different between IDE and SATA on the guest ArcaOS VM?
7) Any other change that you like to tweek on VirtualBox VM config?

Let me know any of your comments if you are using ArcaOS guest on VirtualBox.

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Roderick Klein on December 08, 2021, 09:42:29 pm
Does this not answer some of the questions ?

https://www.arcanoae.com/wiki/arcaos/installation-planning/virtual-machine-configuration/oracle-vm-virtualbox/

Roderick
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 08, 2021, 10:29:24 pm
Good.

It solves the following:

3) Audio: I selected ICH AC97, I guess it has a similar performance as Intel HD and SB with Uniaud.
Arca Noae prefers Sound Blaster 16.

4) Network: The emulated Intel Pro and PCNet adapter works, but I'm not sure if the newer Intel drivers has a better performance. Should I go with Intel?
Arca Noae Prefers Intel Pro.

5) Display: Video Memory: Does it makes any different putting increasing the memory (like to 128MB) ?
Arca Noae says to leave it as default. But it does not says anything the video driver.

6) Storage: Is there any performance different between IDE and SATA on the guest ArcaOS VM?
Arca Noae prefers SATA for HDD and Optical CD-ROM

Nice. In my case I will use Intel HD for audio, since I want to keep testing any future Uniaud.

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 09, 2021, 12:05:29 am
Hi

Just as a related thing I asked on VirtualBox forum where should someone create a new "Type / Version" on the "Create New VM" menú, so ArcaOS 5.0.x can be included.

I was pointed to this segment of the code (https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-all/Global.cpp).

It seems it is hard coded, a new one can be included. This is the one for eComStation.

Code: [Select]
422     { "OS2",     "IBM OS/2",          "OS2eCS",             "eComStation",
423       VBOXOSTYPE_ECS,             VBOXOSHINT_HWVIRTEX | VBOXOSHINT_FLOPPY,
424       1,  256,   4,  2 * _1G64, GraphicsControllerType_VBoxVGA, NetworkAdapterType_Am79C973, 1, StorageControllerType_PIIX4, StorageBus_IDE,
425       StorageControllerType_PIIX4, StorageBus_IDE, ChipsetType_PIIX3, IommuType_None, AudioControllerType_AC97, AudioCodecType_STAC9700  },

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Andreas Schnellbacher on December 09, 2021, 12:04:51 pm
1) Video: Should I select Panorama on the install, or it does not make a different with the default gengrad for VirtualBox?

5) Display: Video Memory: Does it makes any different putting increasing the memory (like to 128MB) ?
Arca Noae says to leave it as default. But it does not says anything the video driver.

The video driver is replaced by the driver from the Guest Additions. My experience is that it doesn't matter. But why let Panorama (or SNAP) create additional non-functional notebook pages in the Screen object? See the first AN screenshot of the installer, below 'ArcaOS Installation'. It has GENGRADD selected.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dariusz Piatkowski on December 09, 2021, 07:27:08 pm
Andreas, everyone...

1) Video: Should I select Panorama on the install, or it does not make a different with the default gengrad for VirtualBox?
...
The video driver is replaced by the driver from the Guest Additions. My experience is that it doesn't matter. But why let Panorama (or SNAP) create additional non-functional notebook pages in the Screen object? See the first AN screenshot of the installer, below 'ArcaOS Installation'. It has GENGRADD selected.

Agreed, unless you specifically want to use functionality provided by a specific video driver.

In my case, every desktop machine here (home) has multiple monitors attached to it. If I want my VM session to span multiple displays (so multi-head) that would require me to deploy SNAP drivers, unless of course the multi-head functionality provided by the HOST OS is sufficient and one simply works in OS/2 as if the display was a real VERY large physical display.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 09, 2021, 11:04:07 pm
Agreed, unless you specifically want to use functionality provided by a specific video driver.

In my case, every desktop machine here (home) has multiple monitors attached to it. If I want my VM session to span multiple displays (so multi-head) that would require me to deploy SNAP drivers, unless of course the multi-head functionality provided by the HOST OS is sufficient and one simply works in OS/2 as if the display was a real VERY large physical display.

Have you tried spanning multiple monitors in a virtual machine? I'd assume that it is mot supported but don't really know.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dariusz Piatkowski on December 09, 2021, 11:13:30 pm
Hi Dave,

Have you tried spanning multiple monitors in a virtual machine? I'd assume that it is mot supported but don't really know.

Nope, not personally...but I recently moved a physical XP install into a VM and was surprised to see so many options...I could have sworn that multi-head was one of them. Needless to say, since my XP image did not make use of this I wouldn't have been able to try it out anyways.

Now I'm thinking that for this kind of a thing to work, you'd have to use a fullscreen VM session to start of with.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 10, 2021, 04:23:19 am
Hi Dave,

Have you tried spanning multiple monitors in a virtual machine? I'd assume that it is mot supported but don't really know.

Nope, not personally...but I recently moved a physical XP install into a VM and was surprised to see so many options...I could have sworn that multi-head was one of them. Needless to say, since my XP image did not make use of this I wouldn't have been able to try it out anyways.

Now I'm thinking that for this kind of a thing to work, you'd have to use a fullscreen VM session to start of with.

Looking into it, at least with Windows, it can work. Need to install the additions, which likely similar to us includes a video driver, set things up correctly in VBox and go with a full screen VM. I'd guess the VBox specific video driver has to support multiple monitors, so unlikely that SNAP would work, I'd assume it is in VBE mode rather then actually supporting your ATI card.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 11, 2021, 08:28:38 am
Hi

Just as a related thing I asked on VirtualBox forum where should someone create a new "Type / Version" on the "Create New VM" menú, so ArcaOS 5.0.x can be included.

I was pointed to this segment of the code (https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-all/Global.cpp).

It seems it is hard coded, a new one can be included. This is the one for eComStation.

Code: [Select]
422     { "OS2",     "IBM OS/2",          "OS2eCS",             "eComStation",
423       VBOXOSTYPE_ECS,             VBOXOSHINT_HWVIRTEX | VBOXOSHINT_FLOPPY,
424       1,  256,   4,  2 * _1G64, GraphicsControllerType_VBoxVGA, NetworkAdapterType_Am79C973, 1, StorageControllerType_PIIX4, StorageBus_IDE,
425       StorageControllerType_PIIX4, StorageBus_IDE, ChipsetType_PIIX3, IommuType_None, AudioControllerType_AC97, AudioCodecType_STAC9700  },

Regards

I sent a patch to the VBox mailing list a while back asking them to add it and was ignored :(.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 11, 2021, 05:00:09 pm
Hi

Just as a related thing I asked on VirtualBox forum where should someone create a new "Type / Version" on the "Create New VM" menú, so ArcaOS 5.0.x can be included.

I was pointed to this segment of the code (https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-all/Global.cpp).

It seems it is hard coded, a new one can be included. This is the one for eComStation.

Regards

I sent a patch to the VBox mailing list a while back asking them to add it and was ignored :(.

Hi jailbird

Maybe we can make some noise to see if ArcaOS can be included on that  VirtualBox list.

Which is the change you suggested? Can you post the code change? Does it match the ArcaOS VirtualBox recommendation Wiki?

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 11, 2021, 05:22:17 pm
I believe Arca Noae already tried to get added to the VirtualBox list and were rejected.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 11, 2021, 05:47:35 pm
I believe Arca Noae already tried to get added to the VirtualBox list and were rejected.

You are right, I found this on the VirtualBox Tickets (https://www.virtualbox.org/ticket/17509).
The rationale for not including ArcaOS is not good enough.
- "Your OS is not readily available. It's available for sale. Only. I can get every single OS out there for a test drive (a.k.a. readily available), except maybe OSX. Yours? No way! "
That is not good enough because they include Windows, IBM OS/2 that are also available for sale. So this guy complains about it, because there is no ArcaOS free demo available.

I think we should write down the template (Code snippet) to support ArcaOS 5.0 and try to create a new ticket. It was opened 4 years ago and closed 2 years ago. We need to try to see if things changed with time.

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 14, 2021, 03:25:37 am
Hi

Just as a related thing I asked on VirtualBox forum where should someone create a new "Type / Version" on the "Create New VM" menú, so ArcaOS 5.0.x can be included.

I was pointed to this segment of the code (https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/src-all/Global.cpp).

It seems it is hard coded, a new one can be included. This is the one for eComStation.

Regards

I sent a patch to the VBox mailing list a while back asking them to add it and was ignored :(.

Hi jailbird

Maybe we can make some noise to see if ArcaOS can be included on that  VirtualBox list.

Which is the change you suggested? Can you post the code change? Does it match the ArcaOS VirtualBox recommendation Wiki?

Regards

Here's the patch that I sent to their mailing list.

Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Lars on December 14, 2021, 07:36:51 am
And you are picking the eCS icon?
Lewis is going to cut you into four :-)
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 14, 2021, 03:01:12 pm
Hi

Can we agreed that the specs are according the ArcaOS Wiki ?

Code: [Select]
+    { "OS2",     "IBM OS/2",          "OS2ArcaOS",          "ArcaOS",
+      VBOXOSTYPE_ArcaOS,          VBOXOSHINT_HWVIRTEX,
+        256,  4,  2 * _1G64, GraphicsControllerType_VBoxVGA, NetworkAdapterType_I82540EM, 1, StorageControllerType_IntelAhci, StorageBus_SATA,
+        StorageControllerType_IntelAhci, StorageBus_SATA, ChipsetType_PIIX3, AudioControllerType_SB16, AudioCodecType_SB16  },
+
I'm not sure what the number order means "256,  4,  2 * _1G64". Is this 1GB of RAM?

Is there a typo on line 103?
Quote
+    { ovf::CIMOSType_CIMOS_ArocaOS,                              VBOXOSTYPE_ArcaOS }
Is it ArcaOS instead of ArocaOS ?

About the icon. Lewis has accepted on the VirtualBox ticket system to use the ArcaNoe logo, but I don't think the project wants to include any official logos. Look that they had created custom logos for Windows, OS/2, Linux, etc, and all seems to be under a similar style. I guess that as a first shot it will be good to use one of OS/2 or eCS logos until some open source logo with the same style is created for ArcaOS.

But I guess we need to take just little steps, let's try first to get the ArcaOS specification approved. I'm thinking on creating a new ticket with this request.

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 21, 2021, 02:17:07 am
Hi

Can we agreed that the specs are according the ArcaOS Wiki ?

Code: [Select]
+    { "OS2",     "IBM OS/2",          "OS2ArcaOS",          "ArcaOS",
+      VBOXOSTYPE_ArcaOS,          VBOXOSHINT_HWVIRTEX,
+        256,  4,  2 * _1G64, GraphicsControllerType_VBoxVGA, NetworkAdapterType_I82540EM, 1, StorageControllerType_IntelAhci, StorageBus_SATA,
+        StorageControllerType_IntelAhci, StorageBus_SATA, ChipsetType_PIIX3, AudioControllerType_SB16, AudioCodecType_SB16  },
+
I'm not sure what the number order means "256,  4,  2 * _1G64". Is this 1GB of RAM?

https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Main/include/Global.h#L69  should help. Looks like there's been changes since I wrote my patch, there should now be a "1, " added on the 3rd line, like:

+        1, 256,  4,  2 * _1G64, GraphicsControllerType_VBoxVGA, NetworkAdapterType_I82540EM, 1, StorageControllerType_IntelAhci, StorageBus_SATA,

Anyways, it means by default, 1 vCPU, 256MB RAM, 4MB video RAM, and 2GB HDD.

That's a lot lower than what I normally use (I normally do 4 vCPUs, 3072MB RAM, and 20GB HDD), but I'm no OS/2 expert, so I thought I'd match it somewhat with the eComstation values.

Is there a typo on line 103?
Quote
+    { ovf::CIMOSType_CIMOS_ArocaOS,                              VBOXOSTYPE_ArcaOS }
Is it ArcaOS instead of ArocaOS ?

About the icon. Lewis has accepted on the VirtualBox ticket system to use the ArcaNoe logo, but I don't think the project wants to include any official logos. Look that they had created custom logos for Windows, OS/2, Linux, etc, and all seems to be under a similar style. I guess that as a first shot it will be good to use one of OS/2 or eCS logos until some open source logo with the same style is created for ArcaOS.

But I guess we need to take just little steps, let's try first to get the ArcaOS specification approved. I'm thinking on creating a new ticket with this request.

Regards

Indeed, total typo :(.  When I wrote this patch it compiled tested, but obviously I missed the typo when I posted it. Sorry about that!
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 21, 2021, 02:45:10 am
Okay, so I guess on the following line in the patch, they also added a field for IOMMU type, which needs to be added. So to make it easier, I'll just spin a new patch for the latest versions of VBox with the typo fixed.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 21, 2021, 03:41:40 am
Okay, here's an updated patch.

Since Lars was worried about Lewis's reaction to using os_os2ecs.png I changed it to os_os2_other.png :).

I defaulted to 1GB RAM (that seems to be what Arca Noae is recommending). It's default to SATA, and not NVMe, since:

- ArcaOS 5.0.7 still doesn't put NVME in the boot image
- VBox doesn't seem to support booting from NVMe when using legacy BIOS booting, only UEFI booting.

So maybe when 5.1 is released we can change it :).


Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Lars on December 21, 2021, 12:46:06 pm
Okay, here's an updated patch.

Since Lars was worried about Lewis's reaction to using os_os2ecs.png I changed it to os_os2_other.png :).
Good man !
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 21, 2021, 01:50:02 pm
Hi

I opened ticket 20741 (https://www.virtualbox.org/ticket/20741) to see what happens.

Regards 
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Eugene Tucker on December 21, 2021, 02:51:15 pm
Okay, so I guess on the following line in the patch, they also added a field for IOMMU type, which needs to be added. So to make it easier, I'll just spin a new patch for the latest versions of VBox with the typo fixed.

You have to use a USB stick and copy the driver to the USB stick and then use the install in the pre boot install menu. ( I am not usre of the correct name but detailed directions are here https://www.arcanoae.com/wiki/nvme/.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 21, 2021, 09:41:58 pm
Okay, so I guess on the following line in the patch, they also added a field for IOMMU type, which needs to be added. So to make it easier, I'll just spin a new patch for the latest versions of VBox with the typo fixed.

You have to use a USB stick and copy the driver to the USB stick and then use the install in the pre boot install menu. ( I am not usre of the correct name but detailed directions are here https://www.arcanoae.com/wiki/nvme/.

Yep. I figured since the idea was to make it easier for people, however, defaulting to a setting where they have to do that isn't exactly user friendly :).  That and since VBox won't be able to boot it in BIOS (CSM) mode anyways..
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Eugene Tucker on December 22, 2021, 02:54:30 pm
They have decided to release this feature in Arca OS 5.1.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: ivan on December 22, 2021, 08:23:05 pm
These comments are interesting but the big question is will we ever get a VBox that actually works using ArcaOS as the host, by that I mean one that does not require fiddling with to get things like USB, large screen monitors, etc working.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Martin Iturbide on December 22, 2021, 11:13:41 pm
Hi Ivan

These comments are interesting but the big question is will we ever get a VBox that actually works using ArcaOS as the host...

I think that is another subject, porting the latest VirtualBox to ArcaOS, I guess it was discussed in the past but I don't remember which was the stopper that does not allows us to have VirtualBox 5.2 or 6 ported to our platform.

Regards
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 23, 2021, 06:01:41 am
I think the latest VirtualBox is basically 64 bit only. Looking on their site, it is claimed that VirtualBox can run in as little as 512MB's of ram but in reality, 4GB's is considered not enough with the minimum recommendation being 8GB's.
We're moving more and more into a 64bit world, developers have tons of ram, most users are now on 64 bit systems, usually with 8GB's minimum, even my old computer has 12 GB's.
It was what I found running VirtualBox on OS/2, kept running out of memory with most guests wanting 2GB's or more. Considering just running SeaMonkey, Thunderbird and a couple of other things, I'm currently using 1.7Gb's of ram, that 1.6GB left over doesn't go very far, especially with our low/high memory division.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: ivan on December 23, 2021, 02:37:11 pm
Hi Dave,

I have to agree with you about 64 bitness - all my Ryzen systems are 64 bit units.  So it seems that for any form of OS/2 to go forward we need to convert it to 64 bit.

Not being a programmer I don't know what that would involve but I think the dumping of the 16 bit programs wouldn't be missed by most people.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Andreas Schnellbacher on December 23, 2021, 06:20:15 pm
Not being a programmer
Me neither. Here's how I understand it:

First you need a compiler that's able to produce code that can address
64 bit of RAM. When that works, you have to rewrite the memory management.
At least the system has to support 64 bit addressable RAM to be able to
assign that to apps. (Guess that part is in the kernel.) Quite a challenge
when you don't have the source code. ;-)

About 16 bit code: OS/2 itself contains much 16 bit code: Almost all drivers,
except ACPI.PSD and CMD.EXE are still 16 bit code. Much fun without the
sources. ;-)

The next step won't be to raise evrything to 64 bit. It is to support PAE
(Physical Address Extension). Then the 4 GB limit would apply for each
process, not, as it is now, for the entire system.

About 16 bit apps: Except some few system apps, I don't use 16 bit apps.
I don't understand why 64 bit code can't support 16 bit code, but that seems
to be the case. Note that for systems with 64 bit addressable RAM
virtualization is always an option.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 23, 2021, 11:43:01 pm
About 16 bit apps: Except some few system apps, I don't use 16 bit apps.
I don't understand why 64 bit code can't support 16 bit code, but that seems
to be the case. Note that for systems with 64 bit addressable RAM
virtualization is always an option.

When AMD designed AMD64, they figured nobody would want segmented addressing and VM86 while in “long mode” (64-bit mode), so they took it out of that mode. They’re both still there in non-long mode (32-bit mode) for backwards compatibility, of course.

I think AMD-V / VT-x work around that by letting you run a virtual 32-bit environment within your 64-world and use those features in there.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 24, 2021, 06:33:28 am
My non-expert understanding,
Jailbird is basically right about why they dropped 16 bit support along with simplifying things a lot.
The compiler is the simple part, along with the linker (wlink fork is 64 bit), the assembly in the kernel is the hard part, it would need rewriting, which even IBM didn't touch.
Similar with most device drivers. Even the 32 bit will make assumptions about the memory being 32 bit. Windows had the same problem.
As Andreas said, there are device drivers, various parts of the main API and actually cmd.exe along with most of the traditional command line programs. They can be replaced.
Then everything would need rebuilding to be 64 bit. Likely even with source there would be hurdles, 32 bit assumptions. You could have a set of 32 bit libraries and such and run as 32 on 64 bit (forget the proper name).
We're missing source and a few skilled kernel people to even start, besides IBM might not allow it.

PAE seems a more possible course, but the kernel needs to support it, not simple. The low/high shared memory model we have might complicate things as well. Even when working, it seems there'd have to be some shared memory taking up that 4GB address space. Still even to give programs separate 2GB address pools would help.

It's manpower, IBM took years to port OS/2 to PowerPC (32bit), with lots of money and manpower. And they had the source and access to some of the people who wrote it.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 30, 2021, 11:10:16 pm
It's manpower, IBM took years to port OS/2 to PowerPC (32bit), with lots of money and manpower. And they had the source and access to some of the people who wrote it.

It’s really sad that all of that PPC work never made it to the x86 version. I’m assuming IBM couldn’t give the changes to AN in source form, as MS still co-owns the source?
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Dave Yeo on December 30, 2021, 11:28:42 pm
It's manpower, IBM took years to port OS/2 to PowerPC (32bit), with lots of money and manpower. And they had the source and access to some of the people who wrote it.

It’s really sad that all of that PPC work never made it to the x86 version. I’m assuming IBM couldn’t give the changes to AN in source form, as MS still co-owns the source?

Some of it did, the Gradd drivers for example came from the PPC version.
As for the source, rumour has it that it was lost. AN doesn't even have the x86 kernel sources, not sure why but perhaps they're also lost.
It would have been nice if IBM had released the PPC source, though how much MS owned is hard to say, might be the problem with the x86 source as well.
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: jailbird on December 31, 2021, 09:15:27 pm
It's manpower, IBM took years to port OS/2 to PowerPC (32bit), with lots of money and manpower. And they had the source and access to some of the people who wrote it.

It’s really sad that all of that PPC work never made it to the x86 version. I’m assuming IBM couldn’t give the changes to AN in source form, as MS still co-owns the source?

Maybe it'll eventually be like the Inktomi/Yahoo! Traffic Server code and somebody will eventually find it sitting on a shelf somewhere...
Title: Re: VirtualBox and ArcaOS 5.0.7
Post by: Doug Clark on January 01, 2022, 09:36:27 pm
On my machine the guest OS in vbox, running on an AOS host machine with dual-head / SNAP can set the screen size equal to the resolution of the AOS host, i.e. 3820 / 1080.  However that screen size is not available on the guest unless the session is started with vboxsdl.  If I start the guest session from  virtualbox.exe the full resolution of the host screen is not available in the guest.

At least that is the case with a Windows NT guest.  Haven't tried with other guest OSs

The other advantage of using vboxsdl is the session usually starts immediately.  If I use virtualBox.exe I usually have to wait 15 seconds after virtualBox.exe comes up before I can start a guest.

The downside is you can't just close the guest session window in order to save the session; you  need to run vboxmanage.exe  to do that.  But that is a minor issue to me.

The command file I use to start my WinNT guest machine is
vboxsdl --startvm dc86c149-cf14-42fb-8833-d81172b92f89

The command file I use  to suspend my WinNT guest session is
vboxmanage controlvm dc86c149-cf14-42fb-8833-d81172b92f89 savestate

The weird number  is the ID of the guest machine.  You can alternately use the title of the guest machine