A2091 ram

graffias79 · 02 August 2018, 17:52

Hi,

I was wondering if anyone knows whether or not I need to populate all of the sockets when adding RAM to an A2091 card. For instance, could I add only 4 chips for 512K? Would that be enough for it to be used as a SCSI controller in an A4000 to control a CD drive? Thanks.

Dynamic_Computi · 02 August 2018, 20:54

It does not seem that you have to fully populate it.

http://www.bigbookofamigahardware.co...t.aspx?id=1161

Adding RAM will help the SCSI speeds, though.

graffias79 · 02 August 2018, 21:12

Ok thanks!

Jope · 03 August 2018, 15:06

The RAM jumper settings tell you which configurations are possible.

Zippy Zapp · 19 August 2018, 04:42

What order do you add the RAM? Bottom 4 sockets first? Do you happen to have a scan of the manual? It doesn't seem to be online anymore at SACC.

Jope · 19 August 2018, 20:10

The innermost vertical column first.

http://www.bombjack.org/amiga/amiga-...(1989_Dec).pdf page 8 of the PDF has the component locations. U14-U17 first.

Zippy Zapp · 20 August 2018, 01:37

Awesome! Thanks Jope! I would have guessed wrong.

Jope · 20 August 2018, 08:20

I hadn't ever given this any thought, as I always fill the A590/2091 with 2MB. :-D

Zippy Zapp · 20 August 2018, 18:56

I usually max out everything too, but I only had 8 chips for 1MB. Turns out I actually had 16 so it was perfect!

Thanks!

graffias79 · 29 August 2018, 23:13

Will the scsi.device for this board conflict with the onboard IDE? Can it handle both interfaces or will one need to be called something else? Not sure how that is normally handled.

shaf · 30 August 2018, 03:46

No there is no conflict because the A2091 device is scsi.device, the A2000 has no ide, there would be a conflict if it was used in an A3000 though. Normally IDE devices are not called SCSI.device. I've used one in an A4000 it works fine the only issue might be the ROM Version if the A2091 BIOS as long as its greater than 6.0 it should be fine.

Jope · 30 August 2018, 08:15

There is no BIOS, as this is not an IBM PC compatible.

The firmware in the A2091 detects that a scsi.device is already resident and renames itself to 2nd.scsi.device (or 3rd.scsi.device etc).

Hewitson · 30 August 2018, 10:44

A lot more devices than IBM PC's have a BIOS (quite a few arcade game systems for example). But I'm sure you already know this.

Jope · 30 August 2018, 11:43

Or is it just a name given by emulator authors to distinguish the motherboard ROM from any swappable cartridge ROMs? (since ROM seems to mean "image of any swappable media, be it disk tape or rom chip" in emulator circles)

I'm interested in a few examples where the HW manufacturer calls it a BIOS. I'm sure there are some.

shaf · 30 August 2018, 19:45

Well in the Amiga work its not called a BIOS but since the ROM updated SCSI Hard Drive Compatibility to support Later Models it could be considered a Updated BIOS for the HD Installer.

thebajaguy · 07 September 2018, 18:58

Amiga vs other environments (like a PC) might be best defined as:

BIOS - as the B implies, is a BASIC Input/Output System - not efficient, but offers the needed communications to get things started at power up. PCs use this to get things 'started'. They generally will load a more robust driver code while the OS is being loaded during system startup. BIOS doesn't care what OS is present, the later driver is specific.

Amiga Driver ROM - The Amiga uses driver code in the ROM to directly support the Amiga Kickstart OS during boot-up. It is not replaced by a higher-level driver.

Rev 6.x scsi.device in ROM supports the A2091/A590 XT drive (8-bit IDE) interface; the 7.0 drops support for XT. This is not compatible with the AT (16-bit) interfaces on the A600/1200/4000.

02 August 2018, 17:52	#1
graffias79 Registered User Join Date: Jul 2018 Location: Madison, WI, USA Posts: 69	A2091 ram Hi, I was wondering if anyone knows whether or not I need to populate all of the sockets when adding RAM to an A2091 card. For instance, could I add only 4 chips for 512K? Would that be enough for it to be used as a SCSI controller in an A4000 to control a CD drive? Thanks.

30 August 2018, 03:46	#11
shaf Registered User Join Date: Jun 2012 Location: Toronto / Canada Posts: 237	No there is no conflict because the A2091 device is scsi.device, the A2000 has no ide, there would be a conflict if it was used in an A3000 though. Normally IDE devices are not called SCSI.device. I've used one in an A4000 it works fine the only issue might be the ROM Version if the A2091 BIOS as long as its greater than 6.0 it should be fine. Last edited by shaf; 30 August 2018 at 03:51. Reason: spelling/grammar correction, additional info.

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02 August 2018, 20:54	#2
Dynamic_Computi 10MARC Join Date: Jul 2018 Location: Tucson, AZ, USA Posts: 214	It does not seem that you have to fully populate it. http://www.bigbookofamigahardware.co...t.aspx?id=1161 Adding RAM will help the SCSI speeds, though.

02 August 2018, 21:12	#3
graffias79 Registered User Join Date: Jul 2018 Location: Madison, WI, USA Posts: 69	Ok thanks!

03 August 2018, 15:06	#4
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,882	The RAM jumper settings tell you which configurations are possible.

19 August 2018, 04:42	#5
Zippy Zapp Registered User Join Date: Sep 2013 Location: CA/USA Posts: 346	What order do you add the RAM? Bottom 4 sockets first? Do you happen to have a scan of the manual? It doesn't seem to be online anymore at SACC.

19 August 2018, 20:10	#6
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,882	The innermost vertical column first. http://www.bombjack.org/amiga/amiga-...(1989_Dec).pdf page 8 of the PDF has the component locations. U14-U17 first.

20 August 2018, 01:37	#7
Zippy Zapp Registered User Join Date: Sep 2013 Location: CA/USA Posts: 346	Awesome! Thanks Jope! I would have guessed wrong.

20 August 2018, 08:20	#8
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,882	I hadn't ever given this any thought, as I always fill the A590/2091 with 2MB. :-D

20 August 2018, 18:56	#9
Zippy Zapp Registered User Join Date: Sep 2013 Location: CA/USA Posts: 346	I usually max out everything too, but I only had 8 chips for 1MB. Turns out I actually had 16 so it was perfect! Thanks!

29 August 2018, 23:13	#10
graffias79 Registered User Join Date: Jul 2018 Location: Madison, WI, USA Posts: 69	Will the scsi.device for this board conflict with the onboard IDE? Can it handle both interfaces or will one need to be called something else? Not sure how that is normally handled.

30 August 2018, 08:15	#12
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,882	There is no BIOS, as this is not an IBM PC compatible. The firmware in the A2091 detects that a scsi.device is already resident and renames itself to 2nd.scsi.device (or 3rd.scsi.device etc).

30 August 2018, 10:44	#13
Hewitson Registered User Join Date: Feb 2007 Location: Melbourne, Australia Age: 41 Posts: 3,773	A lot more devices than IBM PC's have a BIOS (quite a few arcade game systems for example). But I'm sure you already know this.

30 August 2018, 11:43	#14
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,882	Or is it just a name given by emulator authors to distinguish the motherboard ROM from any swappable cartridge ROMs? (since ROM seems to mean "image of any swappable media, be it disk tape or rom chip" in emulator circles) I'm interested in a few examples where the HW manufacturer calls it a BIOS. I'm sure there are some.

30 August 2018, 19:45	#15
shaf Registered User Join Date: Jun 2012 Location: Toronto / Canada Posts: 237	Well in the Amiga work its not called a BIOS but since the ROM updated SCSI Hard Drive Compatibility to support Later Models it could be considered a Updated BIOS for the HD Installer.

07 September 2018, 18:58	#16
thebajaguy Registered User Join Date: Mar 2017 Location: Rhode Island / United States Posts: 203	Amiga vs other environments (like a PC) might be best defined as: BIOS - as the B implies, is a BASIC Input/Output System - not efficient, but offers the needed communications to get things started at power up. PCs use this to get things 'started'. They generally will load a more robust driver code while the OS is being loaded during system startup. BIOS doesn't care what OS is present, the later driver is specific. Amiga Driver ROM - The Amiga uses driver code in the ROM to directly support the Amiga Kickstart OS during boot-up. It is not replaced by a higher-level driver. Rev 6.x scsi.device in ROM supports the A2091/A590 XT drive (8-bit IDE) interface; the 7.0 drops support for XT. This is not compatible with the AT (16-bit) interfaces on the A600/1200/4000.

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