PFS3AIO and DirectSCSI and large IDE HD

[amigasith]

Hi folks,

I read so much tonight about this topic, but could not find an answer... Can anyone please help me with this ?

What I would like to do eventually is to use a large IDE real hard disk (40GB or 80GB) in my A1200 with Kick 3.1, WB 3.1, and PFS3AIO. So first of all, am I right with my thinking that I will definitely need a patched scsi.device (preferably a V43+ if I got it right) in order to be able to utilize the full disk size, since I am planning to use a real hard disk and not a CF / SD card that might give illegal but "good" CHS values?

When using a patched scsi.device, it seems all of them (according to the table here) support NSD and DirectSCSI. So my second question is: Is there any reason to prefer DirectSCSI over NSD or vice versa? Maybe performance? Or this doesn't matter anyway when using IDE? And if so, why?

I learned that I can set the DosType so that PFS3AIO will try DirectSCSI first. So this would be a means to actually prefer one over the other. My last question is then: Is there any way to tell which access method PFS3AIO actually uses after initializing?

I apologize for this plethora of questions but I would like to really understand before moving on...

Thanks for looking

[thomas]

There is no big difference between NSD (or TD64) and DirectSCSI for IDE. Both have to be interpreted and translated into ATA commands.

On true SCSI bus, the DirectSCSI commands are simply passed through to the device by the driver while NSD/TD64 commands have to be translated into SCSI commands. This means that in case of DirectSCSI the file system is responsible to send properly formulated SCSI commands to the device while with NSD/TD64 this is done by the driver. Possible device-specific differences which are implemented in the driver are only taken into account when using NSD/TD64.

So generally NSD is to prefer. DirectSCSI is only a workaround for device drivers which don't support new standards.

In your special case the major difference is that with DirectSCSI you can use the first 7.8 GB of your drive for boot partitions while with (or better without) NSD the limit is at 4 GB.

[amigasith]

Awesome, thanks Thomas This explains most of my questions. But what exactly do you mean by the "without" in

...with (or better without) NSD the limit is at 4 GB

I understand it two-fold like this: (a) with NSD the boot partition has to reside within the first 4 GB of the drive but the rest of the partitions can be virtually anywhere in the drive and (b) without NSD (or any other 64-Bit addressing mode), the total limit for all partitions, not only the boot partition, is 4 GB. Please correct me if I'm wrong

[thomas]

At power-on time the harddrive can only be accessed through the ROM version of scsi.device. This means that the harddrive size is limited to 4GB if accessed with the standard CMD_READ and CMD_WRITE commands and to 7.8 GB when using HD_SCSICMD. There is no NSD or TD64 available at this time.

There is no partition size limit except that of the file system. But of course you cannot make partitions bigger than the harddrive which means that if the harddrive is limited to 4GB, all partitions which need to be accesses at that time (i.e. the boot partition(s)) have to reside entirely inside this space, the first 4GB of your harddrive.

Once the scsi.device patch has been loaded and activated, the harddrive size limit is much bigger: 2 TB for HD_SCSICMD with 512 byte sectors and 17,179,869,184 TB for TD64 and NSD.

Partititon sizes are still limited by the file system which means 104 GB for PFS3.

[amigasith]

Great, thank you very much for your detailed explanation This is one of the things that makes this forum so very special: You (almost) always get extremely good and technically well-founded answers by people like you!

Btw. I am also a big fan of your website - especially the "Große Festplatten mit Kickstart 2.0" article really helped me getting started with my current 4 GB CF card setup. Again, thanks a mllion

[Doc Mindie]

Hmmm.
I've got a problem on my end... I've got a 2.5" IDE of 40GB... I've installed and use Loadmodule Devs:SCSI.device in the startup-sequence, and installed PFS3AIO which I use on partitions that are not *DH0 (ie, sys

my boot partition is roughly 300MB (so well inside the 4GB limit) and at the start of the HD. *DH1: is roughly 3.5GB (taking the total up to around 3.8 for *DH0:+*DH1 and then I made the remaining space (roughly 36GB) on large partition and formatted using PDS\3.

Problem is that after formatting *DH2:, my SYS: became corrupted and I had to reinstall from scrath, formatting *DH0: at the same time.

I used HDToolbox at first, but later switched to HDInstTools, (from the PFS_53 archive) but with the same problem occurring, corruption of *DH0:

Is it a better idea to switch from FFS_DC on the 0: partition to PFS3AIO?

Or is it "simply" that my a1200 IDE is broken?

Or something else alltogether?

btw, I followed the guide of http://eab.abime.net/showpost.php?p=831346&postcount=14 that post when installing, I take it the MaxTransfer doesn't apply if you're using a proper HD instead of an SD-card, but I'm still puzzled as to the results with the 40GB HD

[thomas]

Originally Posted by Doc Mindie

Problem is that after formatting *DH2:, my SYS: became corrupted and I had to reinstall from scrath, formatting *DH0: at the same time.

I suppose you did not use "quick" format? Which format program did you use?

Before OS 3.5 the standard SYS:System/Format program has the same 4GB problem as FastFileSystem: it just wraps around to 0 every 4GB. You should never do a non-quick format on a partition outside the first 4GB.

Generally a harddisk does not need to be formatted. It cannot even be formatted by software. All the "formatting" does, is to fill every block on the disk with garbage. This might be useful if you want to sell the drive. But for normal usage it is not necessary.

Do a quick format. It's sufficient and much faster.

Originally Posted by Doc Mindie

btw, I followed the guide of http://eab.abime.net/showpost.php?p=831346&postcount=14 that post when installing, I take it the MaxTransfer doesn't apply if you're using a proper HD instead of an SD-card, but I'm still puzzled as to the results with the 40GB HD

The MaxTransfer setting works around a bug in scsi.device. It applies to all drives, not only flash memory cards. Only if the drive is old enough to follow the same ATA specs as scsi.device, only then it might not have the MaxTransfer problem. Current ATA specs miss a feature which scsi.device relies on.

[zipper]

FFS DC is better for floppies , I once installed it onto HD and got constant errors - took some time until I recognized the culprit to be the file system.

[Doc Mindie]

I used the format programme that comes with PFS3_53 (from Aminet) and did a full format.... hmmm.

I'll try again. And again. And again. Untill things goes right

Cheers, Thomas and Zipper

PS: I take it I did everything "correct" is that a good assumption?

[thomas]

BTW, the machine boots a lot faster if the boot partition uses PFS3. There is no reason to use FFS on the boot partition.

[Doc Mindie]

Right, cheers.

However, I'm limited to the 4GB as the boot partition, right? Otherwise, where will I load the SCSI.device_A1200 from.

Correct assumption?

[fgh]

Just to be sure - type version scsi.device to confirm that the new version is loaded.
If it is, just do a quick format and you should be fine.

(Using directSCSI (PFS3DS or AiO) 7,87GiB is the limit, not 4GB)

[Doc Mindie]

Ta.

Though I "refuse*" to use a superlarge partition as my sys:

Simply because even OS3.9 doesn't use more than 100MB, so I believe I'm quite safe with my current (approximate) 250MB. Got room for MUI and some other small and nice addons... you know... the things you're "addicted" to... like MultiCX, et.al

* By "refuse" I mean" I don't see the point of a several GB woth of HD dedicated to SYS: All games and projects will be on a different partition, simply because I like it that way.

Kinda like SYS: Work: Games: and Other: style partition setup

[Doc Mindie]

Originally Posted by thomas

The MaxTransfer setting works around a bug in scsi.device. It applies to all drives, not only flash memory cards. Only if the drive is old enough to follow the same ATA specs as scsi.device, only then it might not have the MaxTransfer problem. Current ATA specs miss a feature which scsi.device relies on.

Right. What I meant was "I don't need to change the MaxTransfer to something smaller than default, as I'm using a HD proper and not a SD-card?"

[fgh]

You need to lower it to 0x1fe00 for all drive types (SD,CF,HDD,SSD), except for very old ATA-1 HDDs.
(ATA-1 was replaced by ATA-2 in 1996)

[Toni Wilen]

More correct answer is: "it depends". Some IDE drives still support original ATA-1 behavior, some don't.

[fgh]

Thanks Toni, didn't know that.
The recommendation remains though

[Jope]

Yeah, no point in adding any conditions to that rule of thumb.. It was an arduous process to finally get everyone saying 0x1fe00 with two zeros. :-)

And to give yet another opinion on partitioning: I never understood more than one partition per disk on an Amiga.. As long as you're not using FFS, there's no point in wasting the RAM. Organizing your stuff is not a valid reason for chopping them up, there's the makedir command in C: ;-)

[Doc Mindie]

Originally Posted by Jope

Yeah, no point in adding any conditions to that rule of thumb.. It was an arduous process to finally get everyone saying 0x1fe00 with two zeros. :-)

And to give yet another opinion on partitioning: I never understood more than one partition per disk on an Amiga.. As long as you're not using FFS, there's no point in wasting the RAM. Organizing your stuff is not a valid reason for chopping them up, there's the makedir command in C: ;-)

Ahh. But what if your SYS: becomes corrupted, or there's another problem and you have to format? And frankly.. I feel that by keeping the system proper on a separate partition, and keeping it well defragmented, it boots faster... and then there's always the IF something happens" in which case I just need to reinstall the system, not everything else as well.

Then again.... people are different.... and some like this and others like that

[Jope]

Been using PFS3 since 1998.. Zero HD corruptions so far. Back in the turn of the millennium I used Amigas semi seriously, so there was a lot more IO due to web browsing and so on, and no problems.