VMU

This article is about video game console hardware. For the standard airspeed term, see V speeds.

North American Dreamcast VMU

The VMU, or Visual Memory Unit is a memory card peripheral for the Dreamcast. Its official name was changed by Sega for each of the three key regions:-

• Japan = Visual Memory System (VMS)
• North America = Visual Memory Unit (VMU)
• Europe = Visual Memory (VM)

The name was changed from VMS to VMU for the NA market as the name VMS was already owned and in use by the Digital Equipment Corporation for their VMS operating system. It is not known why the name was changed again to VM for the European market, however the name VMU was commonly used in the UK.

While its most basic function is as a removable storage device, the VMU may also serve as an auxiliary display during normal gameplay and, through use of additional software, act as a handheld game console. Console-like features of the VMU include a small black and white screen, speaker, directional pad, four buttons and the ability to download additional games. Initially only available in white, colors were expanded to transparent Red, Blue, Green, Yellow, Black and many other color variations.

Mini-games

Official Dreamcast 4x memory card

Several titles for the Dreamcast included mini-games that could be downloaded onto a VMU. The Sonic Adventure series, for instance, included the Chao Adventure mini-game. In the game players could transfer Chao eggs to the VMU and play to increase the stats of their hatched Chao, where upon they could upload their improved Chao back into the Dreamcast game. In Resident Evil 2 , Resident Evil 3 and Resident Evil Code: Veronica, it can display the current health condition without having to go to the Weapon Screen.

Dreamcast titles that include VMU games and extra features

• Cardcaptor Sakura: Tomoyo no Video Daisakusen
• Demolition Racer: No Exit
• Dino Crisis
• Evolution 2: Far Off Promise (12 Hour Clock)
• Godzilla Generations (Japanese Version)
• Grand Theft Auto 2
• Jet Set Radio / Jet Grind Radio [USA]
• Marvel vs. Capcom 2: New Age of Heroes
• Namco Museum
• NFL 2K
• NFL 2K1
• NFL 2K2
• Power Stone
• Power Stone 2
• Quake III Arena
• Resident Evil 2
• Resident Evil 3: Nemesis
• Sega GT
• Sega Rally 2 (Stats and Records)
• Shenmue
• Silent Scope
• Skies of Arcadia
• Sonic Adventure
• Sonic Adventure 2
• Soulcalibur (Japanese Version)
• Sword of the Berserk: Guts' Rage
• Tech Romancer
• Time Stalkers
• Tokyo Bus Guide
• TrickStyle
• Virtua Tennis
• Zombie Revenge

Hardware

VMUs attach through either two slots on the controller.

The VMU is plugged directly into one of two slots on a Dreamcast controller. Two VMUs may be plugged in each controller. When operated independently of the Dreamcast console, the VMU acts as a file manager with limited game console functionality. VMUs may also connect to each other directly to facilitate file transfer or multiplayer gaming.

Upon initial use the player is prompted to select from a group of simple bitmap images to serve as the default background for the VMU. This image is displayed while the Dreamcast console is in the operating system menu; it is usually replaced by a simplified logo during regular gameplay. Some titles display custom animations on the VMU's screen during gameplay, while some titles also offer new background images for the unit.

The VMU runs on two CR-2032 lithium batteries which are inserted into the rear of the VMU under a screw-secured lid. Without battery power, the VMU still works as a memory card and auxiliary display, but cannot play downloaded mini-games. Additionally, a VMU without battery power will beep when the Dreamcast is powered on (if the VMU is inserted into a connected Dreamcast controller).

Technical specifications

• CPU: 8-bit (Sanyo LC8670 "Potato")
• Memory: 128KB flash memory. 28KB is reserved for system use leaving 100KB for data storage, which is divided into 200 'blocks' - 1 block equaling 512 bytes.
• Display: 48 dot width × 32 dot height, LCD
• Display size (width×height): 37 mm × 26 mm (1.46 in × 1.02 in)
• Case dimensions (width×height×depth): 47 mm × 80 mm × 16 mm (1.85 in × 3.15 in × 0.63 in)
• Power source: 2 × CR2032 batteries with auto-off function
• Sound: 1-channel PWM sound source
• Weight: 45 g (1.6 oz)

Extra blocks

The VMU has 128KB of flash memory, however by default 28KB is reserved for system use. In recent years homebrew programs like Dream Explorer (aka VMU Tool) have allowed users to unlock an extra 44 blocks (22KB) of this reserved space^[1] increasing the overall VMU capacity to 244 blocks. However, a handful of games might be unable to detect the memory card if this is done, although none have been reported apart from DreamKey/DreamPassport and Metropolis Street Racer.

4x Memory Card

Official 4x Memory Card

Late in the Dreamcasts lifespan Sega released an official 4x Memory Card which offered four times the data storage of a standard VMU, with 800 blocks. It was released in Japan on December 14, 2000^[2] as "Memory Card 4X", and in the USA as "4x Memory Card" However this memory card is designed only for data storage and lacked a screen, speaker, buttons, clock, or a menu system, making it incompatible with VMU mini games, and other VMU features.

The Dreamcast can only access a memory card with up to 128KB of flash memory (The size of a standard VMU) The 4x memory card overcame this limitation by splitting 512KB (4 megabit) of flash memory into four 'pages' each page having 200 blocks of storage. Each of the four pages can be selected using a button on the top right of the card, and one of four orange LEDs will light to indicate which page is currently selected. Some games released before the introduction of the 4x Memory Card were incompatible with it, and Sega released a list of incompatible games.^[3]

A limited edition Phantasy Star Online 4x Memory Card was also released in Japan to coincide with the games release. It was coloured blue and featured the Phantasy Star Online logo printed onto the casing.^[2]

Since the 4x Memory Card was released very late in the Dreamcast's lifespan, it did not make it to retail in Europe despite a planned release (along with the Dreamcast Broadband Adapter which was also unreleased in Europe).

Third-party equivalents

The majority of third party cards did not feature a screen, buttons, speaker, clock, or menu system, making them incompatible with VMU mini games. However, many third party memory cards offered larger storage capacities than the standard VMU, often using a button or switch to select between different banks/pages of 200 blocks (Due to the Dreamcast's 128KB memory card limit)

Nexus Memory Card

The Nexus Memory Card is a third party version of the Visual Memory Unit that features four times the memory of a stock VMU with 800 blocks (4 megabit / 512 kilobytes) but lacks an LCD screen. The card is divided into 4 pages each with 200 blocks, each page can be selected using a button on the top left of the card.^[4] The Nexus Memory Card is slightly larger than the normal VMU and can be connected to a personal computer by USB, Parallel or Serial cable. A 3200 block (16 megabit / 2 megabytes) version of the Nexus is also available, but this model has been known to be unstable.^{[citation needed]}

Nyko Hyperpak

The Nyko Hyperpak was a basic memory card without the screen and VMU buttons. However, it was four times the size of a normal memory unit and also had a switch that would switch the device from memory mode to rumble mode. It was larger than a standard VMU but had no way to connect to a personal computer.

PERFORMANCE Memory Card

The Performance Memory Card was a third-party basic memory card. Although it lacked a screen and buttons, it carried up to 200 blocks of memory. It was much lighter than the standard VMU, but didn't hold VMU game data without deleting its progress first. It is almost exactly the same as a PlayStation memory card, but much larger. Performance also released a "Mega Memory Card", which was a 4X Memory Card, carrying up to 800 blocks in total. The card was divided into 4 Slots of 200 Block cards, which could be changed by moving a switch on the back of the card, each slot being labeled 1-4. However, unlike the official 4X Memory Card and other 3rd party 4X memory cards, the user must remove the memory card, flip the switch to a new slot, and then insert it back in, in order for the Dreamcast to recognize a New Memory Card slot.

See also

• The Sony PocketStation, a similar device for the PlayStation.

External links

• VMU at the Open Directory Project

References

1. ^ "Dream Explorer". http://bswirl.kitsunet.org/vmutool/release/about/?lg=en&menu=. Retrieved 2009-05-31. 
2. ^ ^{a b} "Dreamcast Memory Card 4X Details". http://www.gamespot.com/news/2642229.html. Retrieved 2009-06-07. 
3. ^ "DC Memory Card 4X Compatibility List". http://www.gamespot.com/news/2646823.html. Retrieved 2009-06-07. 
4. ^ "Review: 4X Nexus Memory Card w/PC Link". http://www.segatech.com/technical/nexus/index.html. Retrieved 2009-05-31.