Abstract

Thomas-Conrad commissioned Tolly, as part of the 1994 Industry Benchmark for PCMCIA LAN performance testing, to evaluate the TC5141 PCMCIA Ethernet adapter, with the main focus on measuring notebook Ethernet performance against ISA-based desktop baseline adapters in both ODI and NDIS environments. The project was designed to determine whether mobile users gave up meaningful LAN throughput when moving from desktop PCs to credit-card-sized PCMCIA adapters.  

The November 1994 Technology Spotlight explains that the TC5141 was part of Tolly’s first comprehensive performance study of Ethernet and Token Ring PCMCIA LAN adapters. Tolly notes that notebook users had many product choices but very little hard performance data. The report identifies the TC5141 as a PCMCIA Ethernet adapter supporting both Open Data-link Interface and Network Driver Interface Specification drivers, with PCMDMCS.COM version 1.09 for ODI and PCMNICCS.DOS version 1.7 for NDIS. Page 3 also lists support for BNC or 10Base-T media depending on the supplied media filter.  

In the ODI test suite, the TC5141 performed close to the desktop baseline at larger frame sizes. The Ethernet ODI chart on page 1 shows throughput of 0.8Mbit/s at 64-byte frames, 1.7Mbit/s at 256 bytes, 2.6Mbit/s at 512 bytes, 3.6Mbit/s at 1,024 bytes, and 5.4Mbit/s at 1,512 bytes, versus baseline results of 1.0, 2.3, 3.5, 5.0, and 6.5Mbit/s respectively. With packet burst enabled at the maximum 1,512-byte frame size, the adapter reached 9.5Mbit/s compared with a 9.6Mbit/s baseline. Tolly states that this placed the TC5141 within 0.93% of baseline in that maximum-frame packet-burst case, and within roughly 17% to 28% of baseline at the other tested frame sizes.  

In the NDIS suite shown on page 2, the adapter tracked even more closely to baseline. Tolly reports throughput of 0.8Mbit/s at 81-byte frames, 1.0Mbit/s at 256 bytes, 1.5Mbit/s at 512 bytes, 2.3Mbit/s at 1,024 bytes, and 8.7Mbit/s at 1,514 bytes, compared with baseline results of 0.9, 1.2, 1.8, 2.8, and 8.8Mbit/s. The report states that at the maximum frame size of 1,514 bytes with packet burst, the adapter performed within 1.40% of baseline, and within about 12% to 16% at the other frame sizes.  

The test bed used a Toshiba T1910CS notebook with 12MB of RAM as the PCMCIA client, a Compaq Deskpro 486/66 server with 8MB of RAM, and a 10Mbit/s Ethernet LAN instrumented with a Network General Expert Sniffer and a Hewlett-Packard Series J2300 Protocol Analyzer. Overall, the report presents the Thomas-Conrad TC5141 PCMCIA Ethernet adapter as a strong-performing mobile Ethernet solution that came very close to desktop-class performance, especially at larger frame sizes and with packet burst enabled.