What card should I buy for Linux?

# 2. What card should I buy for Linux?

Contents of this section

For impatient users that just want a quick, cheap answer the summary is: get 16 bit thinnet 8013 cards. For those who want the absolute best performance, get an AMD PC-Net/Lance based card. For more detail as to the who what where and why, read on.

## 2.1 Eight bit vs 16 bit

Unless you are a light user, or are confined to using the smaller ISA slot, the use of the 8 bit cards like the wd8003, the 3c503 and the ne1000 is usually not worth the cost savings. Get the 8013 or the 3c503/16, or the ne2000 instead. (The 3c501 is not included in this discussion, as it shouldn't be used under any circumstances.)

However, so not to leave you with a bad taste in your mouth if you happen to already have one, you can still expect to get about 500kB/s ftp download speed to an 8 bit wd8003 card (on a 16MHz ISA bus) from a fast host. And if most of your net-traffic is going to remote sites, then the bottleneck in the path will be elsewhere, and the only speed difference you will notice is during net activity on your local subnet.

A note to NFS users: Some people have found that using 8 bit cards in NFS clients causes poorer than expected performance, when using 8kB (native Sun) NFS packet size.

The possible reason for this could be due to the difference in on board buffer size between the 8 bit and the 16 bit cards. The 8 bit cards have an 8kB buffer, and the 16 bit cards have a 16kB buffer. The Linux driver will reserve 3kB of that buffer (for Tx ping-pong buffers), leaving only 5kB for an 8 bit card. The maximum ethernet packet size is about 1500 bytes. Now that 8kB NFS packet will arrive as about 6 back to back maximum size ethernet packets. Both the 8 and 16 bit cards have no problem Rx'ing back to back packets. The problem arises when the machine doesn't remove the packets from the cards buffer in time, and the buffer overflows. The fact that 8 bit cards take an extra ISA bus cycle per transfer doesn't help either. What you can do if you have an 8 bit card is either set the NFS transfer size to 4kB, or try increasing the ISA bus speed in order to get the card's buffer cleared out faster.

## 2.2 Low price Ethernet cards

The lowest price seen so far was in the March '94 edition of LAN magazine. There was an ad for Addtron AE-200 cards (jumper settable NE2000 clones) for a measly $19 ea! Unfortunately this offer has since expired. However, you might want to check to see what their everyday price is.

You can also call AT-LAN-TEC at 301-948-7070. Ask for their technical support person. As with all purchases, you should indicate you are buying this for a Linux system. NB: Their current NE2000 clone is a model that `traps' other drivers that probe into their address space. AT-LAN-TEC also carries a clone, non-EEPROM 8013 board for somewhat more, and a NE2100 clone. Either is a better choice if the very lowest price isn't essential.

And a recent addition is the VLB and PCI cards offered by Boca Research. These are selling for around the $70 mark, and these are supported with the latest kernel. These use the new 32 bit versions of the LANCE chip from AMD. See Boca Research for more info.

If you require an ISA card, you can use the the Allied Telesis AT1500 which uses the ISA version of the LANCE chip from AMD. It is offered at a good price by many vendors. Even Inmac, known for their premium markup, has this card for under $100. See AT-1500 for more info.

## 2.3 Vendors and Brands to Avoid

These vendors have decided not to release programming information about their products, without signing a NDA (non-disclosure agreement). Hence it is strongly advised that you avoid buying products offered from these companies.

(1) Cabletron (see Cabletron )

(2) Xircom (see Xircom )

These particular cards should be avoided, as they are obsolete. The reasons as to why they have been classified as such can be found in their respective sections. For your particular application, these reasons may not be a concern, so you should have a read of the reasons listed.

(1) 3c501 (see 3Com 3c501 )

(2) Arcnet based cards (see Arcnet )

(3) Any 8-bit cards (see Eight bit... )

## 2.4 Type of cable that your card should support

Unless you have to conform to an existing network, you will want to use thinnet or thin ethernet cable. This is the style with the standard BNC connectors. See Cables, Coax... for other concerns with different types of ethernet cable.

Most ethercards also come in a `Combo' version for only $10-$20 more. These have both twisted pair and thinnet transceiver built-in, allowing you to change your mind later.

The twisted pair cables, with the RJ-45 (giant phone jack) connectors is technically called 10BaseT. You may also hear it called UTP (Unsheilded Twisted Pair).

The thinnet, or thin ethernet cabling, (RG-58 coaxial cable) with the BNC (metal push and turn-to-lock) connectors is technically called 10Base2.

The older thick ethernet (10mm coaxial cable) which is only found in older installations is called 10Base5.

Large corporate installations will most likely use 10BaseT instead of 10Base2. 10Base2 does not offer an easy upgrade path to the new upcoming 100Base-whatever.

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