LapLink adds Windows, remote control, and synchronizaton that saves time and money on file transfers
Barry Nance
Traveling with a notebook PC is easy, productive, and convenient--but only after you get the right files onto the notebook's hard disk. While you might use a docking station or pocket network adapter to log on to the network and then transfer files from a file server to the notebook, neither of these options is available to you when you're on the road. Copying files to a floppy disk and taking the disk with you is a hit-or-miss proposition, because you might forget to copy a vital file. Furthermore, subnotebook computers often don't have floppy drives. You could use remote access to dial into the central LAN, but remote-access products require nontrivial setup and configuration.
Alternatively, you might use LapLink for Windows to transfer and synchronize files. With LapLink for Windows, you use a serial or parallel cable in the office to transfer files to your notebook. On the road, when you need to make occasional connections to your office computer, you dial in through a modem to synchronize updates to your notebook's files or to transfer updates back to the office. You just leave your desktop PC running LapLink for Windows while you're away.
I evaluated LapLink for Windows 6.0 on an IBM PS/ValuePoint 486/25 and a Compudyne 486/33 notebook. Using the parallel, serial, and network connection features of LapLink for Windows, I transferred files, synchronized files that I modified after the original transfer, exercised a remote PC through LapLink's remote-control feature, and chatted with myself across a LapLink connection. Overall, I found the software easy to install, quick and painless to use, and reliable in everyday use.
It's important to note that LapLink is a feat
ure-rich, Windows-based file-transfer package. If all you need is file synchronization, and you use OS/2 or Unix, you'll be interested in Binary Software Development's UniBeam 1.24 [$189.95 for the OS/2 version, $289.95 for SCO Xenix and SCO Unix; (404) 977-7102].
Multiple Connections
LapLink for Windows is primarily a file-transfer and synchronization utility. You connect two PCs with LapLink over a serial cable (between two COM ports), a parallel cable (between two printer ports), a pair of modems (one PC dials the other), or over a network (two PCs transfer files without using a file server as an intermediary). The package includes color-coded serial and parallel cables. Additionally, LapLink supports wireless connections using AirShare radio modules from National Semiconductor. The range of the wireless connection is only about 30 feet--less than useful for most mobile applications. However, I'm impressed that Traveling Software is at least making the effort to take advantage
of the new technology. LapLink supports over 250 modems, including several cellular and ISDN modems. Over a LAN, LapLink uses IPX (commonly found on NetWare LANs).
To transfer files from a desktop PC to a nearby notebook, you connect the serial or parallel cable between the computers (Traveling Software recommends using the parallel cable for faster transfers). For remote operation through modems, you provide the telephone number and modem type to LapLink. When you install Lap-Link on a computer, you assign it a name. To create a logical connection between two cable-connected machines, you click on the Cable button, use the Connection box to select the other PC's assigned name, and then choose File Transfer, Remote Control, or Chat. For cable-, network-, or modem-based access, you can tell LapLink to automatically reestablish the connection each time you run it.
An interface similar to Windows File Manager lets you point and click on the files you want to transfer. After you select the File Tra
nsfer button on the toolbar, two lists of files and directories appear on your screen. The left list displays the target PC's files; the right shows the other (source) computer's files (see the screen ``
LapLink for Windows
''). You can drag and drop file icons from the right window to the left window to transfer those files. Holding down the Ctrl key during the file selection process lets you transfer multiple files with a single drag-and-drop operation. LapLink will create directories as necessary on the target PC.
Native Windows
This first native Windows version of LapLink takes advantage of the Windows GUI and memory management. You can simultaneously perform multiple tasks over each connection--for example, you can monitor a file transfer in one window, chat with the recipient in a second window, and download E-mail in a third. Traveling Software says it added several video features to keep performance up to par during multiple operations, including intercept
ing GDI (graphics device interface) calls and intelligent video caching.
For security, Lap-Link offers password-restricted access; separate authorizations for file transfers, remote control, and chat functions; remote network log-in; logging of LapLink activities; and callback.
If the target computer has earlier or later versions of the files, you don't have to retransfer entire files to bring one or both computers up-to-date. LapLink's SmartXchange command will synchronize the directories for you. LapLink updates older files that it finds on either PC, but does not delete files.
Cloning directories as well as entire hard drives is also possible with LapLink. You include or exclude subdirectories with a menu option, and you indicate to LapLink whether you want a complete refresh that includes all files in the directory or merely an update of files that exist on both PCs. The synchronization process compares old and new files, then transfers just the changes (deltas) over the LapLink conne
ction. If you have salespeople on the road who need to periodically update large price-list information files, this feature, called SpeedSync, can save hours of file-transfer time.
Technology for Impatient People
Transferring megabytes of files and directories through a parallel or serial cable takes time, especially if you're copying files for the first time. Through a LAN cable, of course, the transfer takes less time. Unless your file server is low on disk space, however, you'd probably just use the DOS XCOPY command, with the /S option, to copy files and directories to and from an intermediate file server. SpeedSync can reduce parallel- or serial-cable file-transfer times considerably, but it's with modem-based connections that SpeedSync really shines.
To discover how well SpeedSync improves modem-based file transfers, I used two Supra 14.4 Kbps modems, with error correction and compression disabled, to connect the ValuePoint and Compudyne computers running LapLink for
Windows. LapLink transferred an entire 1-MB file through the link in 18.48 minutes. I then changed 5 percent of the source computer's file and used SpeedSync to update the target computer. LapLink's Speed-Sync took 1.82 minutes to detect and transfer just the changes to the file. A file whose contents I changed by 10 percent took 3.92 minutes to update on the target computer. Changing 25 percent of the source file caused SpeedSync to take 8.55 minutes to update the target file. The table on the opening page summarizes these results.
SpeedSync itself keeps track of statistics that show how well it has performed. It records the number of bytes that would have been transferred if it hadn't been in effect and the number actually transferred. To see these statistics in LapLink for Windows, you choose SpeedSync Statistics in the SyncTools menu. For the most recent transfer, LapLink displays a graph that contrasts the number of bytes actually sent with the number that would have been sent without SpeedSync.
LapLink for Windows also graphs a history of past SpeedSync-based transfers. As you'd expect, Traveling Software doesn't provide technical details on how SpeedSync works internally.
SpeedSync quickly transfers changes to non-volatile files, but files whose contents change dramatically require longer transfer times. If all or almost all the contents of a file change, SpeedSync can take longer to make the transfer because it must compare the two files before deciding what's changed, and the comparison time adds to the overall transfer time. Also note that SpeedSync doesn't merge the two files, but updates the older file to conform to the newer. The contents of the newer file will always replace the contents of the older file.
LapLink's remote-control and chat features work well. LapLink uses its own video drivers to minimize the transfer time for screen-update material. On each PC, LapLink saves local copies of Windows controls, such as toolbars, bitmaps, or icons. When you move the controls on on
e screen, LapLink only needs to send the identity and new position of the control to the other PC. The LapLink video driver, which works with existing drivers rather than replacing them, also reduces compatibility problems when the two PCs use different screen resolutions or have different brands of video adapters installed.
LapLink for Windows 6.0 is less expensive than most pocket network adapters, works remotely through modems, and can quickly synchronize nonvolatile files when you're away from the office. It is easier to set up and configure than remote-access products, and it offers a useful remote-control feature. LapLink for Windows is an excellent tool for updating, seeding, or cloning PC files.
About the Product
LapLink for Windows 6.0
$139.95
Traveling Software, Inc.
18702 North Creek Pkwy.
Bothell, Washington 98011
(800) 343-8080
(206) 483-8088
fax: (206) 485-6786
illustration_link (30 Kbytes)
If you're familiar with Windows File Manager, you should find navigating drives and directories in LapLink for Windows simple and easy. The program retains the split-screen view of the previous DOS-based versions.
Barry Nance is a BYTE contributing editor and the author of Using OS/2 Warp 3.0 (Que, 1994), Introduction to Networking (Que, 1994) and Client/Server LAN Programming (Que, 1994). You can reach him on the Internet or BIX at
barryn@bix.com
.
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