Abstract

Attachmate Corporation commissioned The Tolly Group to evaluate EXTRA! for Windows version 4.0, with the main focus on comparing its 3270 file-transfer performance against other leading Microsoft Windows-based emulators. The project measured upload and download throughput for both text and binary files using the industry-standard IND$FILE 3270 transfer utility between a Windows workstation and an IBM mainframe over a dedicated 16Mbit/s Token Ring connection.  

The report compares a beta release of EXTRA! for Windows 4.0 with shipping versions of DCA IRMA Workstation for Windows 2.1, Eicon Access for Windows 3.2, IBM Personal Communications/3270 3.00a, NetSoft Dynacomm/Elite 3.4, and Wall Data Rumba for the Mainframe. Tolly’s testing focused on both text transfers, which required ASCII-to-EBCDIC conversion and handling of carriage return and line feed characters, and binary transfers, which simply moved data without translation overhead. Each test was run three times and averaged, with throughput measured on the LAN using a Network General Expert Sniffer.  

In the text-file tests shown on page 1, EXTRA! delivered the highest throughput in both directions, reaching 180KB/s for downloads and 172KB/s for uploads. The closest competitors were NetSoft at 165KB/s and IBM at 149KB/s for downloads, and IBM at 154KB/s and NetSoft at 131KB/s for uploads. In the binary-file tests on page 2, EXTRA! again led the field, reaching 216KB/s for downloads and 254KB/s for uploads. The next-best binary results were NetSoft at 207KB/s download throughput and 163KB/s upload throughput. Tolly highlights that EXTRA! was more than 55% faster than the closest competitor in binary upload tests and 34% faster than the closest competitor in text upload tests.  

The report also explains that traffic characteristics such as frame size, window size, acknowledgments, and frame overhead significantly affected results. Attachmate used 1,053-byte frames for uploads and 2,062-byte frames for downloads, which Tolly notes were common among the vendors. A 1MB file transfer typically completed in about 32 to 49 seconds using between 1,500 and 1,700 frames. By contrast, some competing products required many more frames or showed excessive acknowledgment traffic, especially during uploads. The test bed used an IBM 9370 mainframe running VM/ESA, a Compaq DeskPro 4/33 PC with a 3Com Token Ring card, MS-DOS 6.0, Windows 3.1, and DLC transport. Overall, the report presents EXTRA! for Windows 4.0 as the fastest file-transfer solution in this multi-vendor 3270 emulator benchmark.  

Solutions tested:

• Attachmate EXTRA! for Windows v4.0 — Windows-based 3270 emulator tested for IND$FILE text and binary upload/download performance.  
• DCA IRMA Workstation for Windows v2.1 — Competing Windows-based 3270 emulator included in the file-transfer benchmark.  
• Eicon Access for Windows v3.2 — Windows-based 3270 emulator evaluated for comparative text and binary file-transfer throughput.  
• IBM Personal Communications/3270 v3.00a — IBM 3270 emulator tested in the multi-vendor file-transfer comparison.  
• NetSoft Dynacomm/Elite v3.4 — Windows-based 3270 emulator included in the throughput benchmark.  
• Wall Data Rumba for the Mainframe — Competing 3270 emulator tested for IND$FILE upload and download performance.  

Note: This report was first published under the InterLAB brand but re-branded when InterLAB became The Tolly Group in 1994.