Just tried loading doom from a ramdrive (xmsdsk), and it works fine, it doesn't slowdown. So this confirms that it is somehow related to hard-disk speed or buffering, or caching, or I don't know what exactly.

In Win98, make sure DMA is enabled for the hard disk and that no real-mode drivers are loaded, which may force 16-bit access.

In plain DOS, try "smartdrive /X 4096", it should speed up disk access enough to get rid of the slowdowns.

derSammler wrote:

In Win98, make sure DMA is enabled for the hard disk and that no real-mode drivers are loaded, which may force 16-bit access.

I think the real-mode drivers should show up in the "Performance" tab of System Properties, right? I see "Your system is configured for optimal performance". Everything is 32-bit (File System, Virtual Memory, PC Cards).
DMA was unchecked, so I checked it, restarted, (made sure it was still checked), started doom and... it's the same.

derSammler wrote:

In plain DOS, try "smartdrive /X 4096", it should speed up disk access enough to get rid of the slowdowns.

Just did it too, there's no difference. I also tried 8192, 16384. The same.

Why is this happening? It's so strange. I never had this problem even with really old hard disks and SD/CF card adapters.
I even defragmented the whole hard disk and still no changes.

Tried with a MS-DOS 7.10 boot disk. No luck.

I also tried to use another laptop I bought for next to nothing, a Toshiba 2590CDT, and it suffers from the same problem. I didn't know this but apparently laptop hard disks from this era are somehow very slow for gaming. The game is playable, no problem, but with some small hiccups here and there (opening doors specially, entering new rooms, things like that but it varies).

The only solution I could find so far was loading the game from a ramdrive with xmsdsk.

More info on the subject will be appreciated.

do You run from dos or from windows? did You try to set XMS memory to 16 megs or more and smartdrv C 4096 4096?
do You have some disk overlay stuff running or any other exotic drivers?

mrau wrote:

do You run from dos or from windows? did You try to set XMS memory to 16 megs or more and smartdrv C 4096 4096?
do You have some disk overlay stuff running or any other exotic drivers?

I tried both from dos (msdos.sys BootGUI=0) with no config.sys and no autoexec.bat, and also from within windows and the result is the same.

I'm not loading any drivers or software at all, just starting the game.

There are two configurations for the hard disk in the BIOS, one is "Standard IDE" and the other one is "Enhanced IDE (normal)", I tried them both. They don't make any difference, so I set it to Enhanced IDE (normal).

Total memory in this system is 256 MB. I mentioned in the previous post, I tried smartdrv with 4096, 8192, 16384. It doesn't make any difference.

Maybe I should load some other hard-drive performance enhancer software?

im asking about total extended memory, not how much ram You have;
also smartdrv 4096, 8192, 16384 is incorrect - smartdrv C 4096 4096 but make sure there is a lot of extended memory available, a least 16 megs

It's possible that there is some fault in the hard drive, in addition to 4200RPM being very slow. Although normal for laptops of that era, most desktops were using 7200RPM drives at that time. I would try to obtain a 7200RPM drive for the laptop. It may speed it up noticeably in general.

mrau wrote:

also smartdrv 4096, 8192, 16384 is incorrect - smartdrv C 4096 4096 but make sure there is a lot of extended memory available, a least 16 megs

He was trying with the three values, not using them all at once. Also, your example is actually incorrect. "smartdrv C 4096 4096" assumes that he has DOOM installed on C:, which we don't know. There's no need to pass a drive letter anyway, as smartdrive will cache all local drives per default. Second, if the cache for DOS and Windows should have the same size, you don't pass both values. And finally, while not incorrect per se, never ever use smartdrive without the /x parameter, unless you don't care that a single crash can corrupt the whole hard disk.

tauro wrote:

Why is this happening? It's so strange. I never had this problem even with really old hard disks and SD/CF card adapters.
I even defragmented the whole hard disk and still no changes.

I had that back then as well, when DOOM came out. The reason is simple: there's only a huge WAD file, which is not loaded completely into memory. When level data is reloaded during play and the hard disk is slow, uses PIO, and/or there's no disk cache, the game will freeze while the data is loaded. SMARTDRV however always cured that for me. Also, for DOOM 1 at least, it should not happen any longer if 8 MB of XMS are available.

What's the output of "mem", btw?

mrau wrote:

im asking about total extended memory, not how much ram You have;
also smartdrv 4096, 8192, 16384 is incorrect - smartdrv C 4096 4096 but make sure there is a lot of extended memory available, a least 16 megs

derSammler wrote:

What's the output of "mem", btw?

1Memory Type        Total       Used       Free
2----------------  --------   --------   --------
3Conventional          640K        32K       608K
4Upper                   0K         0K         0K
5Reserved                0K         0K         0K
6Extended (XMS)    260,992K        68K   260,924K
7----------------  --------   --------   --------
8Total memory      261,632K       100K   261,532K
9
10Total under 1 MB      640K        32K       608K
11
12Largest executable program size       608K (622,592 bytes)  
13Largest free upper memory block         0K       (0 bytes)  
14MS-DOS is resident in the high memory area.

dr_st wrote:

It's possible that there is some fault in the hard drive, in addition to 4200RPM being very slow. Although normal for laptops of that era, most desktops were using 7200RPM drives at that time. I would try to obtain a 7200RPM drive for the laptop. It may speed it up noticeably in general.

I think you are right when you say it is slow. It probably has to do with saving energy.
I don't think that there's a fault in the hard drive, because I also tried another similar (slightly older) model (MK6411MAT) which yielded the exact same results. I also exchanged the hard drives between these two laptops (2590CDT and 2800-S202), and the results are also the same in both machines with both hard drives.

I'm using doom2 level 1 for tests because I'm already familiar with the moments when it slows down.

Is that output from plain DOS, or from a DOS box in Windows?

derSammler wrote:

Is that output from plain DOS, or from a DOS box in Windows?

Plain dos (msdos.sys BootGUI=0) with no config.sys and no autoexec.bat

Have you tried software like speedsys to check transfer rates and seek times and such? I have played doom on some quite slow hard drives in the past and I have not noticed any hard drive related slow downs.

I suppose bad sectors on the hard disk might cause the issue because the disk will keep retrying until a timeout is reached. But this would probably last longer than a fraction of a second.

I had a similar experience on a HP OmniBook, though. (P3 1GHz so similar age.) The battery wasn't holding a charge anymore, but with the charger attached I expected this not to be an issue. Unfortunately the flat battery caused some panic NMI or similar regularly, so the machine froze for a very short period all the time. Sometimes this was only noticeable because keypresses were ignored. The solution was to remove the battery.

idspispopd wrote:

I suppose bad sectors on the hard disk might cause the issue because the disk will keep retrying until a timeout is reached. But this would probably last longer than a fraction of a second.

I had a similar experience on a HP OmniBook, though. (P3 1GHz so similar age.) The battery wasn't holding a charge anymore, but with the charger attached I expected this not to be an issue. Unfortunately the flat battery caused some panic NMI or similar regularly, so the machine froze for a very short period all the time. Sometimes this was only noticeable because keypresses were ignored. The solution was to remove the battery.

I'm sure these hard disks don't have bad sectors as I check the SMART information. Thanks for the info about the battery. I use this computer without a battery until some day maybe I'll try and repair it, replacing all the rechargeable batteries inside it.

Baoran wrote:

Have you tried software like speedsys to check transfer rates and seek times and such? I have played doom on some quite slow hard drives in the past and I have not noticed any hard drive related slow downs.

I'm happy to say I completely, absolutely, permanently solved this problem by buying a faster hard disk. No more slowdowns.

HITACHI HTS541040G9AT00, ATA-100, Buffer 8 MB, Average Seek Time 12 ms

I'm not sure what factor made the difference, faster ATA? bigger (x8) cache? What is the most drastic difference?
I ran SPEEDSYS on this system with both hard disks and I'm attaching the logs and pics.