VOGONS


First post, by XtoF

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Hi!

In order to circumvent the 500 MiB limitation of my current IDE drive, I would like to install a SCSI board in my ISA 486 box. As I was not a SCSI user at the time, I did some researches in the forum in order to determine how to set it up.

Now I would like to check that I understood well and I still have a few questions left opened.

I plan to buy an Adaptec 1542CP. It has an internal 50 pin connector and an external 50 pin “high density” connector. As I don’t plan to plug an external device, I will need to buy an external passive terminator.

At first, I will only plug internally a SCSI2SD v5 to act as a hard-drive. Later, I intend to buy a SCSI CD Writer. And here come the questions:

  • I am right if I say that I need a cable sporting IDC50F connectors?
  • Can I test the SCSI board without any device? Do I need an internal terminator in that case?
  • Before I plug the CD Writer in, do I need a terminator in the unused connectors of my cable?
  • The SCSI2SD documentation states that I can disable the terminator by removing some resistors. In which case would I want to do that?
  • Do I need to plug the SCSI2SD at a specific location? The manual states:

    Plug the last connector on the ribbon cable into the connector of the closest internal SCSI device.

    And

    Plug the middle connector on the SCSI cable into the connector of the second internal SCSI device, if there is one.

    Thus, it seems that the connectors are not “neutral”.

The 1542CP is “Plug and Play” and provides a “BIOS”, thus the PC will recognize and boot on the SD card, but I will need EZ-SCSI when installing my CD.

  • Do I need any other kind of software for DOS or Win3.11?

I understand that these questions may seem trivial for someone versed in the dark arts of SCSI, but I prefer to understand them before investing my money in the bards, cables and terminators.

Thus, if you have some answers or precisions for me, you’re very welcome! 😊

Reply 1 of 13, by Errius

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This may help: I have this setup in one of my 486 machines:

Adaptec AHA-1542CP SCSI & floppy controller ISA card
Floppy Controller
Drive A: Sony MPF920-E 3.5" floppy disk drive
Drive B: Panasonic JU-475-5 5.25” floppy disk drive
SCSI Controller
Panasonic CR-508-B SCSI CD-ROM drive
Compaq BB018122B7 18 GB SCSI hard drive with SCA8050 SCA-80 to 50-pin SCSI adaptor
Partition 1: MS-DOS 6.22 (2 GB FAT16)
(16 GB unallocated)

Notes:

The cable (50-pin) does not have a terminator; the hard drive was configured as terminator via jumpers.

Case HDD LED is connected to the SCA8050 as this model of hard drive does not have an external LED connector. This is not optimal as the LED behaves the opposite of expected: ON when drive is idle and OFF when active.

Plug & Play configuration of the Adaptec card could not be used because the card assigns itself resources needed by the Sound Blaster audio card. Manual configuration was necessary. It had to be manually set to port 334 (using switches) and DMA 6 (in SCSISelect utility).

Protagonist: Robot

Reply 2 of 13, by retardware

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To use MSCDEX, you need aspi4dos.sys and aspicd.sys.
Regarding termination, the controllers usually are configured to have terminator on and to supply Term Pwr.
Low-speed SE SCSI with short cables is surprisingly tolerant to missing or faulty termination.
Personally I'd avoid the weird ISAPnP stuff and stick to jumper-configurable hardware on the standard addresses. It is just annoying to have to preboot just to set the PNP stuff to sensible addresses, and then boot some pre-ISAPnP game.

Reply 3 of 13, by gdjacobs

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Some SCSI devices have internal termination capability. Check and see if one of your drives can be set for that.

All hail the Great Capacitor Brand Finder

Reply 4 of 13, by luckybob

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XtoF wrote:
[*]I am right if I say that I need a cable sporting IDC50F connectors? [*]Can I test the SCSI board without any device? Do I […]
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[*]I am right if I say that I need a cable sporting IDC50F connectors?
[*]Can I test the SCSI board without any device? Do I need an internal terminator in that case?
[*]Before I plug the CD Writer in, do I need a terminator in the unused connectors of my cable?
[*]The SCSI2SD documentation states that I can disable the terminator by removing some resistors. In which case would I want to do that?
[*]Do I need to plug the SCSI2SD at a specific location? The manual states:
[*]Do I need any other kind of software for DOS or Win3.11?

OK, in order:

yes, also I would buy a matching terminator for the INTERNAL cable, or get a cable where this is already installed.
yes, and no (in that case)
No
more on that later
no, not really
nothing special

With scsi, both the start and the end need termination. in 9/10 cards it will do this for you automatically on the card end. So all you need to do is terminate the other end of the chain.

Any device that has ability, can work as a terminator. Some devices do this better than others. I prefer to get a cable with a pre-installed terminator, this makes it easy as long as you disable all the drive terminators. If a terminated cable is not possible, I like to use CD/DVD drives as terminators. Again, its a personal choice.

Route the scsi cable in your chassis. Whichever device makes physical sense to be at the end, turn on termination on that device, turn it off on all other drives.

As for software, the same process exists that you do for IDE as you do scsi. The driver changes, but again, the process is identical.

It is a mistake to think you can solve any major problems just with potatoes.

Reply 5 of 13, by XtoF

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Thanks everyone for your answers! 😎
It's now clearer, especially concerning the subject of termination.

I will pass order for the cards and I'll let you know how I configured them.

Reply 6 of 13, by tayyare

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Specifically talking about the card you decided to use:

XtoF wrote:

"As I don’t plan to plug an external device, I will need to buy an external passive terminator."

No, you definately don't need to do that. This card has an auto termination feature that you can enable or diasable thru its own BIOS setup utility (called SCSI Select Utility").

XtoF wrote:
[*]I am right if I say that I need a cable sporting IDC50F connectors? [*]Can I test the SCSI board without any device? Do I […]
Show full quote

[*]I am right if I say that I need a cable sporting IDC50F connectors?
[*]Can I test the SCSI board without any device? Do I need an internal terminator in that case?
[*]Before I plug the CD Writer in, do I need a terminator in the unused connectors of my cable?
[*]The SCSI2SD documentation states that I can disable the terminator by removing some resistors. In which case would I want to do that?
[*]Do I need to plug the SCSI2SD at a specific location? The manual states:
[*]Do I need any other kind of software for DOS or Win3.11?

- If you don't want to deal with a variety of "that pin to this pin" SCSI adapters, it's preferable.
- Yes you can, and no, you don't need any terminator.
- Definately not
- If it is the last device in your cable (i.e. farthest away from the SCSI card) and if your cable does not have an integrated terminator at the end, you don't need to, actually you must leave it as terminator enabled. If you are connecting your CD drive after that device, you need to disable terminatoin on that deivce and enable it on your CD drive (assuming you don't have any integrated/installed terminator at the cable end)
- No, you can install it in any connector on the cable, providing that you take care of proper termination
- With your card, probably not. Sometimes in some older machines DOS cannot recognise a SCSI HDD, and you need to install adaptec drivers for it (and use even adaptec supplied format and partition utilities) but normally it should not happen. For CD Drive, yes you need to intall ASPI and CD drivers. Also for 32bit file/disk access of Windows 3.x, you need to install Adaptec Windows drivers, Genrally, EZSCSI should solve your problems about drivers.

In short, you need to take care of the cable-end termination. It can be done in three ways.

- A cable with an integrated terminator at the end
- İnstalling a proper terminator into the last connector of the cable
- Enabling internal termination of the last device by use of jumpers, etc.

For the card end, you don't need to do anything, since this card has auto termination.

There shouldn't be any other terminators on the chain in any other place, and all the devices except the last one, termination should be disabled.

And don't forget to adjust device SCSI IDs as unique for each device and 0 for boot device.

scsi2.gif
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(*) you don't need a card side termination since your card does that automatically

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And here is the cards documentation if you need it:

ftp://ftp.dyu.edu.tw/pub/Hardware/vendor/ADAP … ig/ig154xcp.pdf

GA-6VTXE PIII 1.4+512MB
Geforce4 Ti 4200 64MB
Diamond Monster 3D 12MB SLI
SB AWE64 PNP+32MB
120GB IDE Samsung/80GB IDE Seagate/146GB SCSI Compaq/73GB SCSI IBM
Adaptec AHA29160
3com 3C905B-TX
Gotek+CF Reader
MSDOS 6.22+Win 3.11/95 OSR2.1/98SE/ME/2000

Reply 7 of 13, by Anonymous Coward

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I recommend getting a 1542CF. It's identical to the 1542CP expect that it has a centronics connector rather than the HD50. I have no end of trouble with HD50 cables. The centronics cables are much more reliable. This of course only matters if you plan on using external devices.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 8 of 13, by XtoF

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tayyare wrote:

Specifically talking about the card you decided to use:

scsi2.gif

(*) you don't need a card side termination since your card does that automatically

Thanks for those illustrations: they're great!
The "termination thing" was the most difficult aspect of SCSI for me to grasp. Now it's crystal clear. 😎

Reply 9 of 13, by DaveJustDave

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I know this isn't a very popular opinion.. but retired enterprise fast SCSI drives are super, super cheap. and those drives come in 10k and 15kRPM varieties. I know some people hate spinning drives, but it's a cheaper alternative.

I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 10 of 13, by yawetaG

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DaveJustDave wrote:

I know this isn't a very popular opinion.. but retired enterprise fast SCSI drives are super, super cheap. and those drives come in 10k and 15kRPM varieties. I know some people hate spinning drives, but it's a cheaper alternative.

We mostly hate the jet-engine noise most of those drives make. 🤣

Reply 11 of 13, by Scraphoarder

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yawetaG wrote:
DaveJustDave wrote:

I know this isn't a very popular opinion.. but retired enterprise fast SCSI drives are super, super cheap. and those drives come in 10k and 15kRPM varieties. I know some people hate spinning drives, but it's a cheaper alternative.

We mostly hate the jet-engine noise most of those drives make. 🤣

The late models of them dont make much noise. Had barely heard them outside the noisy server room, so when i had the task to erase a bunch of Compaq and HP drives in our lab at work i was suprised. Had a P3 Deskpro EN SFF with a loose hotswap 4 drive tray salvaged from a Proliant DL380 connected to an Adaptec 2940 for dBan. Four 15k drives didnt make much noise, but they did get hot so have proper airflow passing over such drives.

Reply 12 of 13, by tayyare

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yawetaG wrote:
DaveJustDave wrote:

I know this isn't a very popular opinion.. but retired enterprise fast SCSI drives are super, super cheap. and those drives come in 10k and 15kRPM varieties. I know some people hate spinning drives, but it's a cheaper alternative.

We mostly hate the jet-engine noise most of those drives make. 🤣

Actually problem with those drives ais not the noise (to me anyway) but their age. They were mostly under heavy use 7/24 during their life time, generally very small amount of usefull life still remained on them.

Don't get me wrong, I love SCSI, all my main retro rigs have a couple of those "retired server disks" in them (36-72-and a few 146 GB variety of many different brands) and they work great (as long as they are working) but be prepared to change them frequently due to total hardware failure. Backing up partition images actually makes this not a big burden, if you have a sizable stash of the aforementioned HDDs on hand.

GA-6VTXE PIII 1.4+512MB
Geforce4 Ti 4200 64MB
Diamond Monster 3D 12MB SLI
SB AWE64 PNP+32MB
120GB IDE Samsung/80GB IDE Seagate/146GB SCSI Compaq/73GB SCSI IBM
Adaptec AHA29160
3com 3C905B-TX
Gotek+CF Reader
MSDOS 6.22+Win 3.11/95 OSR2.1/98SE/ME/2000

Reply 13 of 13, by SirNickity

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1540CF user here. It's a good card, and I especially like that you can disable the BIOS with a DIP switch, so it doesn't run through an obligatory device scan at POST, then again when the driver loads.

Another good option is the 1510. I have one of each, in different builds. The 1510 that I have looks halfway populated, and does not have a BIOS at all, so it's only good for non-boot drives (CD).

I use EZ-SCSI 5 and it detects both of those, and my PCI 2940, and all the devices I've ever attached to it. I consider EZ-SCSI as pretty much mandatory, as you will have a bear of a time finding all the drivers and utilities you need piecemeal, if they exist at all.