differnce between a 2950 xl and a 2950 Cisco switch?

Huge. The 2950XL is a completely different generation from around the time of IOS 11.2 . You *really* don't want the 2950XL these days -- not sold, not supported, much slower than the new series.

WS-C2950-12 WS-C2950-24 WS-C2950C-24 WS-C2950G-12-EI (end of sale) WS-C2950G-24-EI (end of sale) WS-C2950G-24-EI-DC (still sold) WS-C2950G-48-EI (end of sale) WS-C2950ST-24-LRE WS-C2950ST-8-LRE WS-C2950SX-24 WS-C2950SX-48-SI WS-C2950T-24 (end of sale) WS-C2950T-48-SI

You may wish to consider the 2960 or 3560 series, such as the WS-C3560-24PS, WS_C3560-24TS, WS-C2960-24TC-L, or WS-C2960-24TT-L

What's a 2950XL? Never seen one.

Cisco had some long EOL'd switches, the 2924XL switch line ages ago that was pretty popular, but long outdated.

The 2950 is quite a bit newer, and still supported.

If you search cisco.com you will find references to the Catalyst 2950XL series, and to the 3550XL series. They appear to have existed about the same time as the Catalyst 2800 series such as the 2820, 2822, and 2828 (which went EOS April 30 1999). (First time I've ever heard of those...)

Most likely they are typos. Even cisco people make mistakes about their own product lines, given enough models out there.

The 2924XL and 3524XL were such popular products for their time, people probably started mixing up lots of different products with these.

I agree. I did a search a while back for 3550XL. A found a couple of refrences on cisco.com but I came to the conclusion that they were typos. What they realy meant is 3500XL.