September 1994 BYTE). How well they all work together, and how far a notebook vendor takes Microsoft's PnP recommendations, determine how convenient and reliable a docking system is.
As the demand for desktop replacements increases (see
"New Docks Improve Commuter Computers,"
February BYTE), docking notebooks' PnP capabilities gain importance. We tested the PnP features of docking setups from Compaq, Dell, Hewlett-Packard, and IBM, and found that their abilities vary significantly.
Our typical
test setup
included an external mouse, a keyboard, a monitor, and a 10Base-T network connection. For those units with SCSI-2 ports, we attached an NEC MultiSpin 6Xe CD-ROM drive. We also plugged ISA, Peripheral Component Interconnect (PCI), and PC Card devices into expansion slots where
appropriate.
Surprise or VCR
To Win 95, there are only two kinds of docking mechanism: surprise and VCR-style. A surprise mechanism lets you undock the notebook without warning. Win 95 doesn't get a chance to warn device drivers and PnP-aware applications of the event so they can prepare for it. Surprise is the least desirable design, but it's common. There's also no reasonable alternative for port replicators, which must be portable and inexpensive. With this type of system, you should initiate all docking releases through software by using the Eject PC choice in the Win 95 Start menu.
A motorized VCR-style mechanism provides an electrically consistent, secure bus connection and allows the docking station to physically lock the notebook in place. The locking ensures a planned decoupling process that lets device drivers and PnP-aware applications veto an inappropriate undocking, thus preventing data loss or a system hang-up. You unlock and eject either with a physical button o
n the dock or through software. Of the products we tested, only the HP Docking System provides a motorized mechanism. The IBM ThinkPad Dock II, though not motorized, does lock and prevent surprise ejections.
The ability to dock or undock a notebook while it is running (i.e., hot docking) or in suspend mode (i.e., warm docking) is a matter of convenience. Who likes to watch Win 95 reboot itself? When it works, the system takes docking hardware changes in stride, with minimal delay, using Win 95's ability to reconfigure and load device drivers dynamically.
Hot docking is technically more impressive and slightly more convenient. Hot and warm docking are not Win 95 hardware requirements, so cold docking is something you may run into. Also, systems claiming hot or warm docking may do so only under constrained conditions; this is true of the Compaq and IBM machines.
With any new hardware situation, such as a first dock, the Win 95 Hardware Detection window comes up while the configuration manag
er creates a new hardware profile. This takes about 3 1/2 minutes on the 90-MHz notebooks we used in testing. When this process goes wrong--and it will if you make enough hardware changes--the best solution is to undock, delete all docked hardware profiles, and start over once you've determined what caused the problem.
Even when you have everything configured, your PnP problems may not be over. If you have SCSI hard drives hooked to the docking unit, for example, you may have to cold dock (with a reboot) or the drives won't show up in Win 95.
Compaq's Modular Bays
If you consider PC Card slots as expansion slots, Compaq's
MultiBay Expansion Base
for LTE 5000 series notebooks is a full docking station. It replicates I/O ports and provides Ethernet ports (both BNC and RJ-45), but it has no SCSI port or ISA expansion slots. However, the MultiBay Expansion Base has two Type III PC Card slots and spaces for two of Compaq's MultiBay drives (floppy, hard, or CD-R
OM) or batteries.
Because the LTE 5100 also has two MultiBay slots, you can move drive and battery modules between the notebook and the dock, or you can have four batteries charging at once. The Compaq dock has a useful security option that lets you attach a single Kensington cable lock to the docking base and lock the notebook into the base at the same time (by preventing forward movement of the docking lever).
Compaq's docking mechanism isn't motorized or locking, so you can surprise it, though not accidentally. A lever system provides a mechanical advantage and guidance to both docking and undocking. Compaq's manual suggests that you can hot dock and undock, but if the docking station contains any MultiBay drives or is connected to a network, you must reboot to see these devices after docking. We found that hot docking hangs the system about half the time, but it allows access to docked drives and a network connection when it does work. Hot undocking always hung the system.
We determin
ed that warm docking works consistently with docked drives (all of them based on enhanced IDE) and network connections. The system doesn't allow undocking warm, because there isn't any way to suspend it when docked. We noted some occasional quirks. Several times with a cold dock, for example, the notebook's trackstick device stayed active rather than the external PS/2 mouse connected to the dock's mouse port. Also, we had to manually switch between LCD and CRT using the appropriate function key.
Dell's Advanced Replication
Dell's Advanced
Port Replicator
is more than just a port replicator for Latitude notebooks, because it provides a built-in 10Base-T Ethernet port. You can also make it into more of a docking station by connecting it (with one screw) to DeskDock, a plastic base that makes for a more stable docking area. With its sturdy monitor stand, it reduces the footprint of the docking setup. The combined setup costs $299.
As a modified port replicat
or, the resulting docking setup lacks mechanical assistance for making the docking connection, so you must pay more attention to ensure a clean, secure connection. (You hear two clicks if you do it right.) You must also remember to swing out the notebook's two rear feet before docking, or the connection won't work. Two levers, one on each side of the port replicator, release the connection. Also typical for a port replicator, the Dell unit uses a surprise release mechanism, so you must remember to use Eject PC on the Win 95 Start menu to initiate undocking.
The Dell unit is capable of warm docking and undocking. Both kinds worked, though not the same way every time. After a warm undock, the notebook sometimes resumed automatically. Other times, it needed help from the power button. In the latter case, it would occasionally reboot instead of resume.
We also noted a configuration problem if the network cable was connected to the port replicator's 10Base-T port the first time we docked. Win 95's ha
rdware configuration created two hardware profiles (Dock1 and Dock2), one with a network card and one without. We could then set up a NetWare connection, but the spurious configuration created further problems. Win 95 remained confused. The solution was to undock, delete the new hardware profiles, redock with the network cable unconnected for configuration, and then reboot with the cable attached to bring up the network. It works thereafter.
HP Hot Dock
Hewlett-Packard's new
Docking System
for the OmniBook 5000 isn't a full docking station because it lacks drive bays (and a monitor stand). However, it is one of the first docking setups to provide a PCI slot and therefore the capability to drive a fast graphics card. (This is an approach you'll see from numerous vendors this year.) The slot, a direct (not bridged) extension of the PCI bus on the OmniBook 5000, has two ISA slots to keep it company, one of them shared. The HP Docking System is also unusual in that i
t supports hot docking. We tested a prototype of the docking station with a shipping OmniBook 5000CT.
The docking mechanism is motorized. You slide the OmniBook up against it, and it grabs the notebook, drawing it onto the bus connector with a loud whir. The docking station provides a full set of indicator lights and reset, power, and eject buttons.
Pushing the eject button initiates undocking, but under software control (however, a hole allows you to force a release with an unbent paper clip if the system hangs up). Low-friction runners let the notebook slide down its ramp at surprising velocity, so you should be prepared to catch your OmniBook.
We tested hot docking with an SMC EtherEZ 8416 Plug and Play Ethernet card in one ISA slot and an STB PowerGraph 64 graphics card in the PCI slot. Once we logged on to a NetWare network, we could quickly undock and dock at will. Network drives disappeared and reappeared in the My Computer folder as appropriate, and the display switched between ex
ternal CRT and the OmniBook's LCD.
Dock for a ThinkPad
The big, black
ThinkPad Dock II
makes an impressive home for IBM's ThinkPad 750 and 760 notebooks. It's a full docking station with two ISA slots, two drive bays, an Adaptec SCSI bus controller, an extra enhanced IDE connection, stereo speakers, and an array of replicated ports. The whole setup locks with a single key.
The Dock II docking mechanism isn't motorized, but it does prevent surprise releases. As you slide the ThinkPad in on a carriage to join with the docking bus connector, a latch engages. To undock, you suspend or shut down the system and then press the eject button on the Dock II. Through the action of a solenoid, the latch releases.
IBM claims hot docking for the Dock II, but technically it's warm docking because the ThinkPad automatically goes in and out of suspend mode during the process. If you have drives residing in the Dock II, you'll want to cold dock anyway.
After a
warm dock, you can't access any hard drives (IDE or SCSI) connected to the dock. Warm undocking isn't a good idea if you have SCSI drives attached to the Dock II. Icons for docked drives remain in the Win 95 interface. If you access these phantom icons, Win 95 locks up. Also, warm docking occasionally causes a system hang-up. Because the power switch is soft, there's then no way to shut down. As with HP's unit, you must resort to an unbent paper clip to release the notebook. An access hole lets the paper clip activate the release solenoid.
For IBM's corporate customers, one big strength is backward compatibility. The Dock II provided PnP capabilities for the ThinkPad 750 under Windows 3.1 using extra utility software, and it currently supports PnP warm docking under both Win 95 and OS/2 (see the sidebar
"PnP Docking with OS/2"
). The Dock II will also work with new PCI-bus ThinkPads that IBM will introduce in the second quarter of this year. Even better, existing ThinkPads will work in the new
PCI docking station that IBM will also introduce. This is quite a feat: a docking bus with a dual ISA/PCI personality.
Where You Should Dock
If you're buying notebooks as desktop replacements, docking stations are an important consideration. The Win 95 PnP capabilities that these systems provide to differing degrees make the process more convenient. As long as you save data before each docking change, you can use all four tested systems reliably.
Differences in feature sets and pricing prevent some comparisons. The inexpensive Dell setup, as you might expect, provided the fewest capabilities, and the Compaq MultiBay Expansion Base beats the IBM Dock II in price, though their features are almost comparable. Even though its $525 price doesn't include drive bays or a monitor stand, the hot-docking HP docking platform is definitely the best toy.
PRODUCT INFORMATION
DeskDock/Advanced Port Replicator (
Ethernet).......$299
Dell Computer Corp.
Austin, TX
Phone: (800) 613-3355 or (512) 338-4400
Fax: (512) 728-3653
Internet:
http://www.dell.com
Circle 1165 on Inquiry Card.
Dock and Play -- Almost
