3+Share
| Purpose | LAN |
|---|---|
| Developer(s) | 3Com |
| Introduced | 1987 |
| Based on | XNS |
| Influenced | LAN Manager |
| OSI layer | 3 to 6 |
| Hardware | Ethernet, others |
3+Share, also known simply as 3+ or 3 Plus, was a pioneering file and print sharing product from 3Com. Introduced in the early 1980s, 3+Share was competitive with Novell's NetWare in the network server business throughout the 1980s. It was replaced by the joint Microsoft-3Com LAN Manager in 1990, but 3Com exited the server market in 1991.
In 1984, Microsoft announced MS-Net, a framework for building multitasking network servers that ran on top of single-tasking MS-DOS. MS-Net implemented only the basic services for file and print sharing, and left out the actual networking in favor of a virtual system in the form of IBM's NetBIOS. Vendors, like 3Com, licensed the MS-Net system and then added device drivers and other parts of the protocol stack to implement a complete server system.
In the case of 3+Share, 3Com based their networking solution on the seminal Xerox Network Systems (XNS), which 3Com's CEO Robert Metcalf had helped design. XNS provided the networking protocol as well as connections to the underlying Ethernet hardware it ran on, which Metcalf had also helped design. They also modified MS-Net's servers to produce what they called EtherShare and EtherPrint protocols, which could be accessed with any MS-DOS computer that had the MS-Net client software installed.
Internally, 3+Share had a network stack, file and print server modules, disk caching, user handling and more, all running simultaneously inside the DOS memory space. Because they were not limited by the PC memory map, 3+Share could support a megabyte or so of flat memory, breaking the x86 PC's 640 kByte barrier. This was a large amount of RAM for the time.
...
Wikipedia