A: That’s right. It’s a characteristic of Android, the Droid’s operating system made by Google, and it’s something I noted as a weakness when I reviewed the first Android phone over a year ago.

Even though the Droid comes with 16 gigabytes of memory, in the form of a removable card, apps can’t be stored on this memory card. They must be stored in a special area of internal memory, which in the case of the Droid totals only a measly 256 megabytes, about a fourth of one gigabyte. The memory card is reserved instead for things like documents, music, videos and pictures. That limits the total number of apps the phone can hold at any one time.

Google says the amount of internal memory allotted for apps is up to the hardware makers, and notes that the Droid has twice as much as the original Android phone. It also says that makers of complex apps that use things like graphics that are ancillary to the core app itself could theoretically offload these files to the memory cards.

But users of Apple’s competing iPhone can devote nearly all of its 16 gigabytes of memory to storing third-party apps, allowing many more apps to be stored on the phone.

I have all my data (addresses, calendar, notes) stored on my Palm Zire. I’d like to get an iPod Touch, but can’t figure out how to transfer the Palm calendar. Can you help? Or, do you know of any other “smart” handheld that will allow me to import my Palm data and give me Internet/email access?

A: There are various workarounds for doing the transfer to an iPod Touch, but, since you ask, there is another smart phone with great Internet capabilities that comes with a way to do it simply and directly: the Palm Pre. It’s based on a new and different operating system than your Zire is, called webOS, and is designed to sync with wireless contact and calendar sources rather than desktop programs.

But Palm has developed a one-time, one-way utility for transferring data from desktop software used by an older Palm to one of the wireless calendar and contact services with which the Pre was designed to sync. More information is at: http://bit.ly/2ivFI.

I want to buy a new computer and I really like the new iMac with the 27″ screen. I am 72 years old, which is one of the reasons I want the larger screen. Please tell me if you think my buying this iMac is a good idea. Is there some negative aspect of the iMac that I should be aware of?

A: I gave the new iMac with the huge screen a positive review, so I obviously think it’s a good computer. But, if by mentioning your age you mean to imply that you have vision issues, you should be aware that the new iMac’s screen isn’t just physically large, but is high resolution.

That allows it to pack a lot more content onto the screen, but, depending on what program you’re using, it can make the text small. Word processors, email programs and Web browsers usually allow you to enlarge text, but not all programs do.

The Mac itself has a system-wide zooming feature, but that makes some tasks harder to work with. I recommend you go to a store and play with the big iMac for a while to make sure you feel comfortable with its screen resolution.

You can find Mossberg’s Mailbox, and my other columns, online for free at the All Things Digital Web site, http://walt.allthingsd.com.

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability.

I am a longtime Palm user and am wondering if the new Palm Pre smart phone can run all the Palm OS programs I have become used to on my Treo.

The Pre is a clean break with Palm’s former operating system and previous hardware, and was designed as a platform for a new generation of software programs, or apps. It uses a new operating system called webOS, which wasn’t built to run old Palm OS programs.

However, there is a $30 program called “Classic” by a company called MotionApps (motionapps.com) that emulates the old platform and makes your sleek new Pre look and work like an old Palm device. It is intended to allow older programs to run on the Pre inside this virtual environment created by Classic. I haven’t tested it with older third-party programs and so I can’t say how well they work in this emulation mode.

But there are some caveats to this method. First, not all old Palm programs will run inside the Classic environment, or at least run well. The company lists those certified to work well on its Web site. Second, the old apps can’t activate certain features of the Pre, such as the camera. Third, Classic’s maker says it hasn’t yet figured out how to sync the old apps with a computer using Palm’s old, familiar HotSync process.

Can the Palm Pre be used as a modem for my laptop?

Sprint, the carrier that is launching the Pre, says the answer to this question is no. The company says its data plans for the Pre don’t permit that scenario.

I use Time Machine for my Mac, but I would also like the belt & suspenders security of manually backing up my invaluable iCal data on an external hard drive. How would I do that?

It’s easy. Just go into iCal’s File menu, select “Back up iCal…” and you can save a copy of your calendar to any drive connected to your computer, or even to any computer or external drive on a network, or over the Internet, that your Mac can access. To restore your calendar, just go to the same menu, but this time select “Restore iCal…” and then select your backup file.

• You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

Does the new Palm Pre smart phone use the traditional Palm operating system and the many programs that have been written for it?

Palm’s Pre, which is due out later this year to compete with the iPhone and the BlackBerry, doesn’t use this older software, which was once the best smart-phone operating system, but has grown stale. It uses an entirely new operating system called the Palm webOS, which will have to attract developers willing to write new programs for it. It is a clean break from Palm’s previous hardware and software.

How does the Clickfree computer backup system you covered last week compare with Apple’s Time Machine or online backup services like Mozy or Carbonite?

Clickfree simplifies the chore of backing up files to an external hard disk. However, as I noted in the review, it doesn’t back up your whole hard disk, it doesn’t work automatically in the background, and it doesn’t create a backup physically distant from your computer.

Time Machine, which is built into the Macintosh operating system, automatically backs up your entire computer in the background and includes a very easy method for recovering files. It works with external hard disks. But it doesn’t work on Windows PCs, and it doesn’t create a remote backup over the Internet.

Mozy and Carbonite are online backup solutions. Their advantages are that they work unattended and create offsite backups. But they aren’t intended to back up an entire computer, they don’t create a local backup, and they carry service fees.

Does my 13-inch MacBook come with the capability to view PowerPoint files?

No. While Macs come out of the box with the ability to view and create files in the Microsoft Word and Adobe PDF formats, they don’t come with a PowerPoint viewer. In order to view (and create) PowerPoint files on a Mac, your best bet is to buy the Macintosh version of Microsoft Office, which includes PowerPoint itself. There are other methods as well. For instance, Apple’s own lower-priced iWork suite can also open PowerPoint files and create files in the PowerPoint format. And some Web-based office programs, like Google Docs, allow you to view PowerPoint files on Macs.

You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.