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Visual Memory Unit

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(Redirected from VMU)
Vmu.jpg
Visual Memory Unit
Manufacturer: Sega
Made for: Sega Dreamcast
Release Date RRP Code
Sega Dreamcast
JP
¥2,500[1] ?
Sega Dreamcast
US
$? ?
Sega Dreamcast
UK
£19.99[3]
Sega Dreamcast
FR
?F
Sega Dreamcast
DE
DM 59,95[4]
Sega Dreamcast
ES
?Ptas
Sega Dreamcast
AU
$49.95[5] ?
Sega Dreamcast
BR
R$R? ?


The Visual Memory Unit (VMU), referred to as the Visual Memory(ビジュアルメモリ) or VM (and VMS) in Japan is the de facto "memory card" for the Sega Dreamcast. While its most basic function is as a removable storage device, the VMU can also serve as an auxiliary display during normal gameplay and, through the use of additional software, it can act as a console independent of the Dreamcast.

Hardware

The introduction of the VMU was considered quite radical in 1998, for as well as being a means of storing Dreamcast data, it acts as its own independent handheld "console", capitalising on a craze started by Bandai with its Tamagotchi device in late 1996. When plugged into a Dreamcast controller it can act as an extra screen, but if removed it becomes a system with its own D-Pad, A, B Mode and SLEEP buttons.

In order to function on its own, a VMU requires two CR2032 batteries, which can lead to problems. It does not require batteries in order to function within a Dreamcast controller (when the controller is connected and the system is powered on), but if the VMU lacks power it will make a high pitched warning screech during the console's bootup to alert the user.

Two VMUs can be connected together (another idea copied from Bandai, this time in its 1997 Digital Monster range, opening up new possibilities such as transferring data or playing two-player games.

Like the controllers and console, there are many different flavours of VMU in terms of colours. The colours vary depending on the market - in Japan there were many novelty VMUs, often inspired by games. In North America, translucent coloured VMUs were released, while in Europe very few coloured VMUs were sold.

The VMU technically debuted four months before the Dreamcast console, with the release of the Atsumete Godzilla: Kaijuu Dai Shuugou VMU in July 1998. As well as being a self-contained game in itself, it can be treated as a Dreamcast memory card.

Criticism

While the VMU is considered an integral part of the Dreamcast console, the built-in screen and its arguably superfluous features led to a high price point when compared to memory cards of the PlayStation and Nintendo 64. Furthermore, initial shipments of Dreamcast consoles did not come with VMUs, and as the Dreamcast has no built-in memory (unlike the Sega Saturn), an extra purchase was required to save games (and comparitively few games were offering alternatives such as passwords than had been the case earlier in the decade).

Despite the higher price, capacity is comparable to the original PlayStation, with both claiming to have 1Mb (128kB) of storage data. Sega did not offer an official non-screened memory card until December 2000, when the 4x Memory Card was released in Japan. The "4x" in this instance symbolises the 512kB of data available to users, though as each 128kB chunk is treated as a separate card by the console, it is much the same as purchasing four separate VMUs.

With the PlayStation, Sony opted to divide its memory cards into 15 blocks (thought to be around 64kB of memory each). The majority of PlayStation games use a single block to save (regardless of whether the full 64kB is used), and while some games are known to use as many as four blocks, their scarcity means PlayStation memory cards are almost guaranteed to house save data for 10-15 titles. With the Dreamcast, no such guarantee was in place - while 200 blocks (about 512 byes each) are available, no rules were put in place to stop developers from filling a memory card with the save data of just one game.

The widely publicised "VMU games" also take up save blocks. Anyone wanting to play, for example, Chao Adventure, a free VMU download in Dreamcast launch title Sonic Adventure, will need to reserve 128 blocks of memory just for this game. Users often find themselves needing reserve a VMU specifically for this purpose, as while in this the 72 remaining memory blocks could still be used for smaller titles, larger games like Shenmue require more than 72 blocks to save (Shenmue needs 80).

In addition, some save games cannot be transferred between VMUs (indicated with a red border in the Dreamcast's file manager), and as with the PlayStation, VMUs in anything other than the first port of the first controller may not be detected by software (although this practise is far less common than on Sony's machine). Rune Jade is notorious for its VMU usage, demanding 198 blocks of memory, despite, in most cases, not using all of it.

The 200 block limit is also artifically restricted, with Sega reserving memory for VMU system functionality, most of it going unused. Third-party tools have since been developed to reformat VMUs to tap into some of this unused memory, creating a further 44 blocks in the process without degrading system performance. However, some games (such as Metropolis Street Racer) will not recognise this extra memory, and third-party memory cards are not guaranteed to be expandable in the same way.

Unlike modern consoles, VMUs lack lithium-ion rechargable batteries (seen in the Game Boy Advance SP and newer), and so their batteries need to be replaced manually on a fairly regular basis. When a Dreamcast system is turned off, no signal is sent to the VMUs to shut down, and so operate on their own power source for a short period of time before automatically switching themselves off. If left unchecked, this can cause VMUs to drain power just by being plugged into a Dreamcast console (although the internal clock means VMUs always lose power when batteries are inserted).

With four controllers and eight powerless VMUs plugged in, each will screech in unison when the system is turned on. No settings exist in either the VMU or Dreamcast BIOS to prevent this (although third-party cards without speakers are unaffected), and can be offputting for users unaware of this feature.

Like many handhelds of the era, the VMU does not have a backlit (or frontlit) screen, and so is difficult to see in low-light conditions. Hardware modifications can be made to circumvent this, however no official solution was ever offered (or even discussed) while the Dreamcast console was on sale.

Legacy

While few Dreamcast games made full use of the Visual Memory Unit, its design and many of the concepts it pioneered would be adopted by several future video games consoles. It has also received aftermarket software support from dedicated fans.

In Japan, Sony began marketing a similar product for its PlayStation line, the PocketStation, as early as January 1999, and while the device was not sold outside its home country, it is thought that nearly five million units were sold before it was discontinued. PocketStation memory functions can only be accessed when plugged into a PlayStation, however dozens of PocketStation games could be downloaded from PlayStation discs. Connectivity between Sony handheld consoles would later be explored with the PlayStation Portable and PlayStation Vita.

Nintendo is generally associated with pushing the idea of a secondary screen, starting with the "Game Link Cable", which allows a Game Boy Advance to be connected to a Nintendo GameCube, first seen in 2001. The concept was revisited, albeit with greater emphasis on the dual screen idea, with the Wii U console in 2012, with ideas being brought over to its successor, the Nintendo Switch in 2017.

Smartphones, which saw a rise in adoption during the late 2000s, have also been used by video games as secondary screens, however without direct connections, most are relegated to displaying static content, often similar in nature to how many Dreamcast games utilise the VMU when plugged into a controller.

Reading save data

When reading save data from the memory manager on the Sega Dreamcast BIOS, it will appear in this format.

Save Data
Name File Name Comment File Size
Name of the file. Name of the file as it appears within the system. Additional Information of File. Number of Blocks Used.

How each file is named and what the comments field represents depends on how the developer has written each descriptor. When reading other articles on Sonic Retro and Sega Retro, keep in mind these common symbols represented in the wiki to determine the text as these variables are likely to differ when viewing on the Memory Manager.

[##] - Number

[MM] - Month

[DD] - Day

Technical specifications

47 mm (1.85")
80 mm (3.15")
16 mm (0.63")


  • CPU: Sanyo LC86K87 (8-bit CPU, energy saving)[6]
  • Memory: 128 KB (200 blocks)
  • Power source: Two CR2032 batteries with auto-off function[6]
  • Display: 48 dot Width x 32 dot Height resolution,[6] Monochrome
  • Display size: 37 mm (1.46 inches) Width x 26 mm (1.02 inches) Height
  • Sound: PWM sound chip,[6] 1-channel PWM sound source
  • Mass: 45g (0.099 pounds)

List of VMUs

Japan

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Code Name Box scans Images Region Date Price Documentation Description
HKT-7001 Atsumete Godzilla: Kaijuu Dai Shuugou
あつめてゴジラ〜怪獣大集合〜
HKT-7001 VM JP Godzilla.png
VMU Godzilla Green HKT-7001 Back.JPG




JP 1998-07-30 ¥2,500
HKT-7002 Visual Memory
ビジュアルメモリ
HKT-7002 VM.png
VMU JPN US.png




JP 1998-11-27 ¥2,500 (2,625)[7]
HKT-7005 Mothra Dream Battle
モスラドリームバトル
HKT-7005 VM.png
VMU JPN US.png




JP 1998-12-23 ¥? HKT-7002 (with software) and figurine
HKT-7006 Gamera Dream Battle
ガメラドリームバトル
VMU DC JP Box Back HKT-7006.jpgNospine.pngHKT-7006 VM.pngVMU DC JP Box Spine2 HKT-7006.jpg
VMU JPN US.png




JP 1999-03-25 ¥? HKT-7002 (with software) and figurine
HKT-7007-03 Visual Memory Colour Version (Aqua Blue)
ビジュアルメモリ・カラーバージョン (アクアブル)
HKT-7007-03 VM JP AQUABLUE BOX.png
HKT-7007-03 VM JP AQUABLUE.PNG




JP 2000-03-01 ? ¥2,500 (2,625)[8]
HKT-7007-04 Visual Memory Colour Version (Lime Green)
ビジュアルメモリ・カラーバージョン (ライムグリーン)
HKT-7007-04 VM JP LIMEGREEN BOX.png
HKT-7007-03 VM JP LIMEGREEN.PNG
VMU Clear Green MK-50122 Back.JPG




JP 2000-03-01 ? ¥2,500 (2,625)[8]
HKT-7007-05 Visual Memory Colour Version (Passion Pink)
ビジュアルメモリ・カラーバージョン (パッションピンク)
HKT-7007-05 VM JP PASSIONPINK BOX.png
HKT-7007-05 VM JP PASSIONPINK.PNG
VMU Passion Pink HKT-7007-05 Back.JPG




JP 2000-03-01 ? ¥2,500 (2,625)[8]
HKT-7007-06 Visual Memory Colour Version (Smoke)
ビジュアルメモリ・カラーバージョン (スモーク)
HKT-7007-06 VM JP SMOKE.PNG




JP 2000-03-01 ? ¥2,500 (2,625)[8]
HKT-7007-16 Visual Memory Clear
ビジュアルメモリ クリア
VMU 7007-16 Clear Mint.jpgHKT-7007-16 VM JP CLEAR BOX.png
HKT-7007-16 VM JP CLEAR.jpg
VMU Clear HKT-7007-16 Atrás.JPG




JP 2000-12-01 ? ¥2,500 (2,625)[9]
HKT-7007-17 Virtual Memory Sonic Team version
ビジュアルメモリ ソニックチームバージョン
VMU JP SonicTeam Box.png
VMU JP SonicTeam.jpg




JP 2000-12-21 ? ¥?
HKT-7007-18 SGGG (Segagaga) Virtual Memory
SGGG (セガガガ) ビジュアルメモリ
VMU DC JP Box Back SGGG.jpgNospine-small.pngHKT-7007-18 VM JP SGGG BOX.png
HKT-7007-18 VM JP SGGG.PNG




JP 2001-03-29 ¥? See also Segagaga
HKT-7008-01 Super Inventor Boy Kanipan Playing Kid DCDC
超発明BOYカニパン あそんでキッドDCDC(デシデシ)
HKT-7008-01 VM JP BOYKANIPAN box-2.jpgNospine.pngHKT-7008-01 VM JP BOYKANIPAN box-1.PNG
HKT-7008-01 VM JP BOYKANIPAN.jpg




JP 1999-04-22 ¥?
HKT-7008-02 Giant Channel
ジャイアントチャネル
HKT-7008-02 VM JP GIANTCHANEL box.PNG
VMU JP GiantGram.jpg
VMU Giant Channel HKT-7008-02 Back.JPG




JP 1999-05-20 ¥?
HKT-7009-01 Visual Memory US Blue
ビジュアルメモリ USレッド
VMU DC JP Box Back HKT-7009-01.jpgNospine-small.pngHKT-7009-01 USBlue box.jpg
VMU Blue.jpg




JP 2001-11-01 ? ¥2,500 (2,625)[10]
HKT-7009-02 Visual Memory US Red
ビジュアルメモリ USブルー
HKT-7009-02 USRed box.jpg
VMU Red.jpg




JP 2001-11-01 ? ¥2,500 (2,625)[10]
DD Visual Memory: Pearl White
ビジュアルメモリ:パールホワイト
DD VM JP PEARLWHITE.png




JP 2000-08-31[11] ¥2,800[11]
DD Visual Memory: Pearl Blue
ビジュアルメモリ:パールブルー
DD VM JP PEARLBLUE.png




JP 2000-08-31[11] ¥2,800[11]
DD Visual Memory: Pearl Pink
ビジュアルメモリ:パールピンク
DD VM JP PEARLBLUE.JPG




JP 2000-08-31[11] ¥2,800[11]
DD Visual Memory: Pure Black
ビジュアルメモリ:ピュアブラック
DD VM JP PUREBLACK box.png
DD VM JP PUREBLACK.jpg




JP 2000-12-21[12] ¥2,800[11][12]
DD Visual Memory Clear Red
ビジュアルメモリ クリアレッド




JP 2000-11-30 ¥? Site: Announcement. Christmas Lottery (30-11~20-12) Might be the same as HKT-7009-02.
DD Visual Memory Capcom version
ビジュアルメモリ カプコンバージョン
DD VM JP CAPCOM.PNG




JP 2000-12-22[12] ¥2,800[12]
DPB Visual Memory: Camouflage
ビジュアルメモリ:迷彩色
DPB VM 2000POINTS box.png
DPB VM JP CAMOUFLAGE.png




JP 1999-03-01 ? ¥2000 DPB points
DPB Visual Memory: Carbon Black
ビジュアルメモリ:カーボンブラック
DPB VM 2000POINTS box.png
VMU JP CARBONBLACK.jpg




JP 1999-03-01 ? ¥2000 DPB points
DPB Visual Memory: Wood Grain
ビジュアルメモリ:木目調
DPB VM 2000POINTS box.png
VMU JP WOODGRAIN.PNG




JP 2000-09-01[11] ¥2000 DPB points
DPB Visual Memory: Leopard
ビジュアルメモリ:豹柄
DPB VM 2000POINTS box.png
DPB VM JP LEOPARD.png




JP 2000-09-01[11] ¥2000 DPB points
DPB Visual Memory: Marble
ビジュアルメモリ:大理石調
DPB VM 2000POINTS box.png
DPB VM JP MARBLE.png




JP 2000-09-01[11] ¥2000 DPB points
DPB Visual Memory: Strawberry version
ビジュアルメモリ:イチゴバージョン
DPB VM 2000POINTS box.png
DPB VM JP STRAWBERRIES.png




JP 2001-05-17 ? ¥2000 DPB points
DPB Visual Memory: Dolphin version
ビジュアルメモリ:イルカバージョン
DPB VM 2000POINTS box.png
DPB VM JP DOLPHINS.png




JP 2001-05-17 ? ¥2000 DPB points
DPB Visual Memory: Number version
ビジュアルメモリ:ナンバーバージョン
DPB VM 2000POINTS box.png
VMU JP DirectNumber.jpg




JP 2001-05-17 ? ¥2000 DPB points
HDR-0089 bundle
VMU JP SakuraTaisen.jpg




JP 2000-05-25 PACK-IN
HDR-0148 bundle
HDR-0148 Sakura Taisen VM.jpg
VMU Sakura Wars 3 bundle Back.JPG




JP 2001-03-22 PACK-IN
T-46301M bundle
T-46301M Di Gi Charat Fantasy VM.png




JP 2001-09-06 PACK-IN
Seaman ~Forbidden Pet~ ??
シーマン~禁断のペット~ ?? 同梱
DC SEAMAN (clear) VM.PNG
VMU Seaman Forbidden Pet Back.JPG




JP 1999-07-29[13] PACK-IN
Hello Kitty Dreamcast Set (Blue Skeleton) bundle
Hello Kitty ドリームキャストセット (と"スケルトンブルー) 同梱
DC HelloKitty (Blue) VM.PNG




JP 1999-11-25[14] PACK-IN Site: [1]
Hello Kitty Dreamcast Set (Pink Skeleton) bundle
Hello Kitty ドリームキャストセット (スケルトンピンク) 同梱
DC HelloKitty (Pink) VM.PNG




JP 1999-11-25[14] PACK-IN Site: [2]
Dreamcast model: Seaman Christmas package bundle
ドリームキャスト model:SEAMAN クリスマスパッケージ 同梱
DC SEAMAN (xmas) VM.PNG




JP 1999-12-19 PACK-IN
Dreamcast CODE: Veronica LIMITEDBOX bundle
Dreamcast CODE: Veronica LIMITEDBOX 同梱
DC BIOHAZARD VM.PNG




JP 2000-02-03 PACK-IN Site: Announcement
Dreamcast Sakura Taisen model bundle
ドリームキャスト サクラ大戦モデル 同梱
DC SakuraWarsDCforInternet VM.PNG




JP 2000-12-01 PACK-IN Site: [3]
Sakura Wars Contest VM




JP ¥?

US

The U.S. standard VM is undistinguisable from the Japanese counterpart. However, the colour series has slightly darker casing and has grey (instead of white) buttons (notice the starking difference between the Dreamcast inscription and the button colours). The US red and US blue Japanese VMs described above are a domestic release of their overseas versions, sporting the U.S. grey buttons and are only distinct by their different packaging.

Code Name Box scans Images Region Date Price Documentation Description
MK-50120 Visual Memory Unit
VMU Branco Blister back.jpgNospine.pngVMU US Box Front.jpg
VMU JPN US.png
VMU Branco back.jpg




US $?
MK-50121 Visual Memory Unit (clear blue)
VMU US Box Back.jpgNospine-small.pngVMU Blue US Box Front.jpg
VMU Blue.jpg




?
MK-50122 Visual Memory Unit (clear green)
VMU Green US Box Front.jpg
VMU Green.jpg




? A similar (or same) is included with the Holiday Gift Pack.
MK-50123 Visual Memory Unit (clear red)
VMU Red US Box Front.jpg
VMU Red.jpg
VMU Clear Red MK-50123 Back.JPG




? A similar (or same) is included with the Holiday Gift Pack
MK-50124 Visual Memory Unit (clear yellow)
VMU amarelo Back.jpgVMU Yellow US Box Front.jpg
VMU Yellow.png
VMU Yelllow Clear MK-50124 Back.JPG




?
MK-50124 Visual Memory Unit (clear yellow)
VMU Yellow US Box-2 Front.png
VMU Yellow.png
VMU Yelllow Clear MK-50124 Back.JPG




?
MK-50125 Visual Memory Unit (clear black)
VMU Black US Box Front.jpg
VMU Black.JPG
VMU Black Clear MK-50125 Back.jpeg




?

Europe

The standard PAL VM is different from the Japanese and U.S. devices as it does not have a spiral next to the Dreamcast inscription, and the inscription itself is made in a larger font.

Code Name Box scans Images Region Date Price Documentation Description
MK-55120 Visual Memory
VM PAL Box Back.jpgNospine.pngVM PAL Box Front.jpg
Vmu.jpg




EU €?

List of incompatible games

By the time the Dreamcast launched, saving games on console was well established across the gaming industry, meaning it was widely expected that any Dreamcast game would be compatible with the Visual Memory Unit (this is in contrast to the Sega Saturn, where although an internal memory saving option was available, many games were still built around a password system).

As such, unlike other Dreamcast accessories, it is more useful to list games that are not compatible with the VMU (and by extension, any Dreamcast memory card). Demos aside, the number of games which utilise a memory card is quite small and only applies to certain genres (South Park: Chef's Luv Shack for example is a multiplayer quiz game so has nothing worthwhile to "save").

Patents

Physical scans

Sega Retro Average 
Publication Score Source
100 №216, p66[15]
Sega Dreamcast
100
Based on
1 review

Dreamcast, US

VMUInstructionManualU.pdf
Manual
Dreamcast, BR
VMU-DCBRTop.jpg
VMU-DCBRBack.jpgVMU-DCBRSide1.jpgVMU-DCBRFront.jpgVMU-DCBRSide2.jpg
VMU-DCBRBottom.jpg
Cover
VMUDCBRManual.pdf
Manual

References


Sega Dreamcast
Topics Technical Specifications (Hardware Comparison) | History (Development | Release | Decline and Legacy) | List of Games
Hardware Dreamcast consoles in Japan (Special) | Overseas
Add-ons Dreamcast Karaoke | Dreameye
Controllers Controller | Arcade Stick | Fishing Controller | Gun (Dream Blaster) | Race Controller | Maracas Controller | Twin Stick | Keyboard | Mouse | Third-party
Controller Add-ons Jump Pack (Third Party) | Microphone | VMU (4x Memory Card | Third Party)
Controller Connectors DC Tsunaident 123 | Dream Connection 2 in 1 | Dream Connection 4 in 1 | Dream Connection II | Super Converter 3 | Total Control | Total Control 2 | Total Control Plus | Total Control 3 | Total Control 5
Development Hardware Dev.Box | Controller Box | Controller Function Checker | Sound Box | GD-Writer | C1/C2 Checker | Dev.Cas | GD-ROM Duplicator
Online Services/Add-ons Dreamarena | SegaNet | WebTV for Dreamcast | Modem | Modular Cable | Modular Extension Cable | Broadband Adapter | Dreamphone
Connector Cables Onsei Setsuzoku Cable | RF Adapter | Scart Cable | S Tanshi Cable | Stereo AV Cable | VGA Box

Dreamcast MIDI Interface Cable | Neo Geo Pocket/Dreamcast Setsuzoku Cable | Taisen Cable

Misc. Hardware Action Replay CDX | Code Breaker | Kiosk | MP3 DC | MP3 DC Audio Player | Treamcast | Third-party
Unreleased Accessories DVD Player | Zip Drive | Swatch Access for Dreamcast | VMU MP3 Player
Arcade Variants NAOMI | Atomiswave | Sega Aurora