jimmy@denwa.info.com (Jim Gottlieb) (11/29/90)
Usually, we use the 8-bit Ethercard Plus in our systems running Interactive 2.2 + TCP/IP 1.2. Is there any reason not to move up to the 16-bit card (I know we have to get the latest drivers from WD)? It's not that much more expensive. A recent post mentioned problems with the Ethercard Plus in 33MHz systems. Likewise, we had problems with it (the 8-bit version) in our Olivetti M380/XP-9 machines (basically a 33MHz version of the AT&T 6386E WGS). We switched to the 3Com 3C503 and all was fine. Our video card (Olivetti supplied) doesn't have the option to switch it into 8-bit mode. I wonder if the 16-bit Ethercard Plus would have worked.
tmh@bigfoot.FOKUS.GMD.DBP.DE (Thomas Hoberg) (12/04/90)
In article <707@denwa.uucp>, jimmy@denwa.info.com (Jim Gottlieb) writes: |> Usually, we use the 8-bit Ethercard Plus in our systems running |> Interactive 2.2 + TCP/IP 1.2. Is there any reason not to move up to |> the 16-bit card (I know we have to get the latest drivers from WD)? |> It's not that much more expensive. |> |> |> A recent post mentioned problems with the Ethercard Plus in 33MHz |> systems. Likewise, we had problems with it (the 8-bit version) in our |> Olivetti M380/XP-9 machines (basically a 33MHz version of the AT&T |> 6386E WGS). We switched to the 3Com 3C503 and all was fine. Our video |> card (Olivetti supplied) doesn't have the option to switch it into |> 8-bit mode. I wonder if the 16-bit Ethercard Plus would have worked. I am all confused! I remember to have read that with the AT bus design a 16-bit peripheral will automatically use up 128k of memory space (something to do with the signals available on the connector). This is probably not true for peripherals in the I/O space (disk controllers and the like) and I can't really believe it's true for LIM 3.2 type memory boards (such as the first Intel Above Board), that use a single 64k window. However I recently experienced trouble with a VGA board that was jumpered for 16-bit ROM access, thus over- laying our Adaptec's ROM area. Rejumpering for 8-bit access solved the problem (and we use shadow RAM anyway for DOS; Unix could not care less about ROM). I really wonder whether there is any advantage to using a 16-bit Ethernet card then, other than having a couple more IRQ lines available. The WD Ethercards use only a 16k window and I guess nobody could afford to waste 128k of address space for that. In any case the bandwidth provided by an 8-bit slot should be quite sufficient for a 10Mb Ethernet. Somebody in this newsgroup said, that the performance difference between Mylex's 32-bit EISA Ethernet card and a WD8003 was in the order of 5%, I'd really like a confirmation on that, though. ---- Thomas M. Hoberg | UUCP: tmh@prosun.first.gmd.de or tmh%gmdtub@tub.UUCP c/o GMD Berlin | ...!unido!tub!gmdtub!tmh (Europe) or D-1000 Berlin 12 | ...!unido!tub!tmh Hardenbergplatz 2 | ...!pyramid!tub!tmh (World) Germany | BITNET: tmh%DB0TUI6.BITNET@DB0TUI11 or +49-30-254 99 160 | tmh@tub.BITNET
james@bigtex.cactus.org (James Van Artsdalen) (12/05/90)
In <200@bigfoot.first.gmd.de>, tmh@bigfoot.FOKUS.GMD.DBP.DE (Thomas Hoberg) wrote: > I am all confused! I remember to have read that with the AT bus > design a 16-bit peripheral will automatically use up 128k of memory > space (something to do with the signals available on the connector). This is correct. Any memory on the AT bus that is 16 bits wide occupies the entire 128K area it's in. There are two sets of addresses: LA<17:23> and SA<0:19>. LAs are valid when BALE is high. SAs are valid on the trailing edge of BALE. The problem is that in order to tell the system that it's a 16 bit cycle, you have to drive MEMCS16 quickly, before waiting for the trailing edge of BALE. So you must use LA<17:23>, which only has granularity to 128K. Bummer. > This is probably not true for peripherals in the I/O space (disk > controllers and the like) Right. > and I can't really believe it's true for LIM 3.2 type memory boards > (such as the first Intel Above Board), that use a single 64k window. Not right. The AT memory controller doesn't know what's out there. The rules are the same for everyone: if it's memory, and it's 16 bit, it's 128K wide. > However I recently experienced trouble with a VGA board that was > jumpered for 16-bit ROM access, thus over- laying our Adaptec's ROM > area. Rejumpering for 8-bit access solved the problem [...] This is a very common problem. If you have a 16 bit video ROM at C000:0, you can't have a hard disk controller with 8 bit ROM at C800:0 or even D800:0. On the other hand, it might be possible to get away with an 8 bit VGA ROM and a 16 bit w/RAM network card. If your system shadows the VGA ROM before the network card is turned on, then there might never be a time when there is a conflict. Same thing for unix - unix will never use the VGA ROM again, so once the network card is turned on and bent on messing up the VGA, you'll be safe. -- James R. Van Artsdalen james@bigtex.cactus.org "Live Free or Die" Dell Computer Co 9505 Arboretum Blvd Austin TX 78759 512-338-8789
lws@comm.wang.com (Lyle Seaman) (12/13/90)
tmh@bigfoot.FOKUS.GMD.DBP.DE (Thomas Hoberg) writes: >In article <707@denwa.uucp>, jimmy@denwa.info.com (Jim Gottlieb) writes: >|> 6386E WGS). We switched to the 3Com 3C503 and all was fine. Our video >|> card (Olivetti supplied) doesn't have the option to switch it into >|> 8-bit mode. I wonder if the 16-bit Ethercard Plus would have worked. You don't need to have an option to switch a 16-bit board into 8-bit mode, just put it in an 8-bit slot. >I really wonder whether there is any advantage to using a 16-bit Ethernet card >then, other than having a couple more IRQ lines available. The WD Ethercards >use only a 16k window and I guess nobody could afford to waste 128k of address >space for that. In any case the bandwidth provided by an 8-bit slot should be >quite sufficient for a 10Mb Ethernet. I can't understand why you can't give up 128k of address space, unless your machine is maxed out on RAM. Most machines have limits at 16M, and 128K isn't a whole lot, compared to that. I don't know what the bandwidth of the PC bus is, but it's not as simple as you think. To keep an Ethernet card pushing data out at 10Mb/s, you can either 1. keep the bus running at 10Mb/s constantly, or 2. blast data across the bus occasionally, buffer it on the card, and dribble it out at 10Mb/s. Doing (1) is pretty difficult (impossible), so you have to resort to (2). That's what a 16-bit card with extra RAM does for you. Furthermore, it's doubtful that the older cards would be able to get data out at 10Mb/s even under condition (1). -- Lyle Wang lws@comm.wang.com 508 967 2322 Lowell, MA, USA uunet!comm.wang.com!lws The scum always rises to the top.