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View Full Version : Not really happy with my NEC v20 build -> harddisk controller mess up..



Robin4
December 17th, 2013, 02:46 PM
Some months ago i was busy with one of my retro computers to build with.

I had put this system in an other case i still have.
My setup is as follows:

Clone ST JUKO motherboard
V20 processor, without co-processor.
1024KB memory; 640, 384.
Connor SCA 80 1GB harddisk
1.44MB floppy drive
1.2MB floppy drive
Creative SB 1.5 with CMS CT-1320C
Roland MPU-IPC-T Midi interface
Intel above Ram board with 2048KB EMS memory
ATI VGA wonder XL 512KB with bus mouse.
Floppy controller with bios.

I messed already to much with that harddisk and scsi controller.. I defentily can say it worked.. But when indexing the harddisk (DIR command) at the first time, its very slow. It just hangs for a few seconds. And yes its just annoying!
I also tried a much smaller drive like 231MB one, but it still hangs when i using the (DIR) command at the first time..
Already some months ago a also tried an 80MB drive, and it still exist.. So the problem doesnt relay on the harddisks iam using.
I also tried some other controllers.. I have two from future domain (with bootrom installed) TMC-850M type on and a yellow one (i thought it could be an older 850m i guess. i really dont know..
The yellow one i only can set 4 memory adresses, the green one is better in mine opinion and i could set 5 memory addresses..
I have also got an NEC T128, but same as the yellow one i only can set 4 memory addresses.. But it seems the biosrom doesnt work anymore.. When i bought it just worked.
I have also an NEC T100 here, but this thing is without the bootrom.. I really dont know where i could find an bios image..

Other thought, iam thinking to mess with the rll harddisks.. I really dont want mfm, because they are to small for my uses..
Do you people know if XT-IDE is still available?? I have an IDE controller here, but that supports only XT-IDE.

SpidersWeb
December 17th, 2013, 04:29 PM
Use DOS 3.3, make some 30Mb partitions, I suspect you'll find it behaves better.

If it was a controller issue, every thing you loaded off disk would be slow, not just directory listings, it sounds like the calculating free space routine is taking too long to finish on the 8088 (V20) which I've noticed even on my 486 machines (although it's only a second) with large drives and DOS 6.

Trixter
December 17th, 2013, 10:08 PM
But when indexing the harddisk (DIR command) at the first time, its very slow. It just hangs for a few seconds. And yes its just annoying!

I answered why this happens over on another thread (http://www.vintage-computer.com/vcforum/showthread.php?29458-Harddisk-response-not-quick-on-the-first-time-used-command-DIR&p=305997#post305997). Yes, it's annoying, but it only happens the first time you type DIR. Type it a second time and it returns immediately.

PeterNC
December 18th, 2013, 05:00 AM
The same happens when I access a 360MB IDE HDD on my IBM 80486 over LapLink from my IBM 8086s & V30. :D

fatwizard
December 18th, 2013, 05:16 AM
I have a Seagate ST01 scsi controller in my IBM 5160 running IBM DOS 3.3. I have the scsi routed to an external 80meg Quantum partitioned 30, 30, 20 meg, and the original 20 meg MFM is drive C:. The first directory listing always pauses much longer on the scsi than the MFM drive.

Stone
December 18th, 2013, 05:50 AM
The XTIDE Tech Support Thread:

http://www.vintage-computer.com/vcforum/showthread.php?19591-XTIDE-tech-support-thread (http://www.vintage-computer.com/vcforum/showthread.php?19591-XTIDE-tech-support-thread)

discusses this observation as it relates to large drives on older machines.

Trixter
December 18th, 2013, 06:20 AM
I have a Seagate ST01 scsi controller in my IBM 5160 running IBM DOS 3.3. I have the scsi routed to an external 80meg Quantum partitioned 30, 30, 20 meg, and the original 20 meg MFM is drive C:. The first directory listing always pauses much longer on the scsi than the MFM drive.

I would posit that your SCSI drive is much slower than your MFM drive, or your SCSI controller does not use DMA.

geoffm3
December 18th, 2013, 01:43 PM
The same happens when I access a 360MB IDE HDD on my IBM 80486 over LapLink from my IBM 8086s & V30. :D

Can you set up a Laplink connection to access a remote drive under a normal drive letter in DOS? I was wondering about that. Never did much with Laplink back in the day.

Stone
December 18th, 2013, 01:50 PM
Laplink doesn't provide you with a normal drive letter as you put it. It gives you a Norton Commander-like format with one pane on the local machine and the other pane on the remote one. No drive letters are harmed in the process. :-)

Robin4
December 18th, 2013, 03:50 PM
Use DOS 3.3, make some 30Mb partitions, I suspect you'll find it behaves better.

If it was a controller issue, every thing you loaded off disk would be slow, not just directory listings, it sounds like the calculating free space routine is taking too long to finish on the 8088 (V20) which I've noticed even on my 486 machines (although it's only a second) with large drives and DOS 6.

Then i have the problem i cant no use the upper memory part to load drivers in. Thats why i choose ms-dos 5.00 instead of compaq dos 3.31
You also saying `some 30Mb partitions` But actually you only can make two of those on one disk, and not more.


I have a Seagate ST01 scsi controller in my IBM 5160 running IBM DOS 3.3. I have the scsi routed to an external 80meg Quantum partitioned 30, 30, 20 meg, and the original 20 meg MFM is drive C:. The first directory listing always pauses much longer on the scsi than the MFM drive.

Then we have almost the same thoughts.. I was already thinking to go with the RLL route.. I have seen movies on youtube, and you just see those tipical drives are much faster on reaction..
Only i really dont want MFM, because for me till 40MB of disk space is a little bit limited for my. I dont want to just install 8 games or so.. really want to install more games and software on that computer. Like Word perfect, and everyting i want to try out..
So i was thinking about 100MB disk minimal..


The XTIDE Tech Support Thread:

http://www.vintage-computer.com/vcforum/showthread.php?19591-XTIDE-tech-support-thread (http://www.vintage-computer.com/vcforum/showthread.php?19591-XTIDE-tech-support-thread)

discusses this observation as it relates to large drives on older machines.

I really dont know if thats the way to follow.. I dont know if the pcb`s are still available.. Then i need to know the costs for to buy the components to solder them on the pcb..
Iam not that stupid to pay about 120 US dollars for a custom made controller.. That rediculous to me.. After all that wont be a cheap controller board.

Stone
December 18th, 2013, 04:15 PM
I really dont know if thats the way to follow.. I dont know if the pcb`s are still available.. Then i need to know the costs for to buy the components to solder them on the pcb..
Iam not that stupid to pay about 120 US dollars for a custom made controller.. That rediculous to me.. After all that wont be a cheap controller board.I didn't suggest that anyone should get anything related to an XTIDE card!!!

I simply stated that *that thread* had some excellent discussion about WHY an 8088 processor takes so damn long to calculate the free space on a very large drive! GEEZ!!! Go back and re-read my suggestion.

Chuck(G)
December 18th, 2013, 06:35 PM
In my opinion, the V-series (V20, V30) NEC CPUs should not be installed strictly for the reason of obtaining faster speed; subjectively, you'll never notice it. Rather, the compelling reason for me was the x186/x286 instruction set that some programs require.

Trixter
December 19th, 2013, 06:17 AM
In my opinion, the V-series (V20, V30) NEC CPUs should not be installed strictly for the reason of obtaining faster speed; subjectively, you'll never notice it.

It was good enough to change some games from "tedious" to "bearable".

vwestlife
December 19th, 2013, 06:34 AM
In my opinion, the V-series (V20, V30) NEC CPUs should not be installed strictly for the reason of obtaining faster speed; subjectively, you'll never notice it. Rather, the compelling reason for me was the x186/x286 instruction set that some programs require.

The V30 has a bigger performance gain over the 8086 (about 20% to 30%) than the V20 has over the 8088 (10% to 20%).

Trixter
December 19th, 2013, 07:10 AM
If you trust the metric code in TOPBENCH (http://dosbenchmark.wordpress.com) (exercises every instruction, memory speed tests, has a "3-D" metric that is MUL and DIV heavy, etc.) then based on the Score the results are:

IBM PC: 4
IBM PC (NEC V20): 6
1.5x improvement

AT&T 6300 PC: 8
AT&T 6300 PC (NEC V30): 12
1.5x improvement

Machines with slower memory bandwidth (system or video) don't fare as well:

IBM PCjr (8MHz hack): 7
IBM PCjr (8MHz hack, NEC V20) 9
1.28x improvement

IBM PS/2 Model 25/25L: 9
IBM PS/2 Model 25/25L (NEC V30): 12
1.33x improvement

The biggest limiting factor in the "feel" of any system is I/O. My stock 5160 is very enjoyable to work with because I'm using it with a CF card connected to an IDE adapter that uses DMA. The same principle holds with modern systems: My Windows 7 system boot-to-usable time went from 7 minutes to 45 seconds when I migrated the OS and APP drives over to SSD.

Chuck(G)
December 19th, 2013, 10:07 AM
Maybe it makes a difference if you're a gamer, but I submit that games do not represent what a typical workload might have been back in the 80s. Even though I was a very early adopter of the V20 for the 5150 (I worked with the folks at NEC USA in Natick, MA in exploring this approach), I could never subjectively determine a difference in performance in what I did as everyday work.

One thing that performance benchmarks rarely account for (and this is not to disparage TOPBENCH in any way) is what a typical mix of I/O and instructions were back in the day--and what those instructions typically were. Again, there are lies, damned lies and benchmarks, to paraphrase Mark Twain--or whoever he got that famous quote from.

Subjectively, I found that a performance improvement takes about 2X to feel "real", no matter where it comes from.

Your mileage, of course, may differ.

vwestlife
December 19th, 2013, 10:36 AM
FYI, in addition to installing a V30 or V30 chip, there is an easy, free performance boost for XT class systems: use PKLITE -d to decompress any executables that have been compressed with PKLITE (such as many of the programs that come with DOS 6 and later). The .EXE and .COM files will of course get bigger, but it eliminates the slight but noticeable delay of the CPU uncompressing the PKLITE'd file in RAM when you load it.

Of course it helps most on a 4.77 MHz 8088, but I can still notice a difference on a 9.54 MHz V20. I leave the files PKLITE'd on floppy disks to save disk space, but once I copy them to the hard drive I un-PKLITE them.

Trixter
December 19th, 2013, 10:51 AM
Maybe it makes a difference if you're a gamer, but I submit that games do not represent what a typical workload might have been back in the 80s.

We don't disagree.


a typical mix of I/O and instructions were back in the day

This is why I mentioned I/O as a bigger determining factor in my previous post.

Robin4
December 25th, 2013, 04:55 PM
I made this v20 system, because i also want to play very first dos games, that runs much better on an V20 then an 286 machine.. And the machine is also for vintage collection, keep that in mind.
And yes a v20 is more nicer to have then an 8088 computer.. In runs windows 3.0 just nice.. And can use the turbo button the slow it down..