Antisocial Hardware?

87C751 asks: "Over the weekend, I happened upon a deal: 10/100 PCI NICs for $1.99. I bought two and installed one in my Linux box. The box came up to POST, and the new NIC started looking for a DHCP server (which I thought was cute, if useless). Once that timed out, boot sequence continued to the message "NTLDR not found"! In an attempt to do a PXE net boot, the new NIC had -rewritten my boot sector!- Granted, a few minutes with a GRUB boot floppy set things right again, but why in the world is J. Random piece of hardware arrogant enough to frob my disc? Has anyone else been bitten by antisocial hardware?"

Comments

Re:Why do you bother spewing nonsense?

[penguinboy]

The NIC can't run anything. There's no flash or EPROM on it. There's no way for it to force the CPU to execute code. I't can't do a damn thing but perform I/O instructions.

Let's read up on PC hardware initialization, shall we?

Adapter cards on the I/O bus can be configured to present an initialization program in ROM memory somewhere in the middle 128K of free addresses. In hex , these addresses are represented as C0000 to DFFFF. Each time the system is initialized, the POST program scans this area for initialization programs and runs any that it finds. This mechanism allows the display adapter to initialize itself properly (no matter which vendor or model of adapter card you own). Code on the SCSI card makes up to two SCSI disks visible and usable to DOS programs. Code on the LAN adapter will boot a diskless workstation from a LAN server.

I guess you aren't entirely wrong: this isn't really 'forcing' the CPU to do anything, since it exists by design.

Yes, I'm quite sure

[87C751]

No PXE server on my network. Just a Netgear RM356 and a SMC Barricade WAP router that the new card was plugged into. And yes, the boot sector was actually changed. I had to reinstall GRUB to get the machine to boot again, and this box has never had NT installed. (it's dual-boot, but Win98 is the other OS)

I still have another NIC, so I could repeat the experiment. I might, too, just to try to dissect the mechanism at work.

Re:Beware the cheap NIC

[identity0]

Okay, I'm not a networking expert but I did stay at a Holiday Inn Express last night(and am taking a class in networking). Here's my somewhat quick explanation:

IP adresses exist so that you can abstract away the hardware on the network. For example, let's say you have a Linux box with IP of 192.168.1.1 and MAC address of XXXX. You can take that box out, and replace it with a Win2k box of IP 192.168.1.1 and MAC address of YYYY. Anything that needed to talk to 192.168.1.1, can still do so without worring about the underlying hardware, or the MAC address having changed. If you rely on the MAC address only, you'd have to change network settings each time you change servers, or even network cards. Using the MAC address would make sense only if there were something that needed to be sent to one NIC, and only that NIC.

Using IP addresses makes networks far easier to organize, too. You can have a network setup where:
Mail server - 192.168.2.1
DNS server - 192.168.2.2
FTP server - 192.168.2.3

...and so on. The addresses are organized, and you don't have to worry about them changing each time there's an upgrade. If you used only hardware addresses:

Mail server - 43HuI87j2H21
DNS server - 5e776uiWE25
FTP server - U089MN5dw2

...and it would change constantly, making networking a huge headache. As an analogy, think about the phone or mail system - you don't have to change your phone # or mailing address each time you change phones or put up a new building on site, as long as no two lines/buildings have the same address. I hope this helps.