标签: pdp

Note: This "How it used to be" story told by Benny Attar truly takes me back in time. When I started with Cirrus Designs back in 1981, we had a single PDP 11/23 computer that we all shared (we each had a VT100 terminal and a keyboard on our desks). The single hard disc supported 1 megabyte and there was only one directory / folder. I can remember when we got a VAX running the VMS operating system where we each had our own directory trees... it all seemed so revolutionary back then (grin). After completing my studies in a technical college in 1984, I joined the Services – never mind what service, that's classified – and was put in charge of the computer room. In those days, all the computers were in a central location, with restricted access, climate control, raised floors, and servants to look after them. Ordinary mortals had computer terminals and printers connected to the computer room through RS232 lines at 9600 baud (the longer lines wouldn't work beyond 4800 baud – for some lines we even had current loop converters). Almost all our equipment came from DEC – we had a couple of PDP11/70's ( I remember being told they cost $120,000 each), a PDP11/44, and a VAX 730. The VAX 750's came later, then the 8300 and 8500 series, then things got smaller with the micro-VAX 3500, 3200 and 3100 computers in the early 90's. The end users were given VT100 and VT102 monochrome monitors, and mighty heavy to carry around they were. The VT100 had a bug in the firmware, if you hit a certain sequence in setup – esc-shift-3 then q, I think it was – you would get a screech from the keyboard speaker. One of our programmers wrote a program that mimicked the terminals' setup screen. Run the program, and apparently you would be locked for eternity in setup. Data storage was on a bank of 6 removable disc drives, each the size of a washing machine and holding 67 megabytes. Of course, we had the mandatory reel-to-reel tapes and 8 inch floppies. I was in charge of a small team of "computer operators" – there did exist such a job description once – who ran the daily backups, changed printer ribbons (the ribbons were packed as mobius loops so they'd be used on both sides), distributed printer paper (fanfold with sprocket holes) and taught new personnel how to operate a terminal ("Press setup-0 to reset the terminal...). One of my young operators went on to complete 2 engineering degrees and a doctorate in computer science, and is now a senior research scientist in the field. We also had some Evans and Sutherland graphics computers for one of the projects involving tactical map displays. The controllers were housed in their own cabinets, with backplanes full of PCB's – mostly TTL standard logic and some 2901 bit-slice processors. We had just 2 colour displays, giant table sized cabinets with 21 inch displays and huge temperamental power supplies. They needed constant adjustment to keep the red, green and blue beams aligned, they needed degaussing with an external degauss ring, and they kept blowing transistors in the deflection amplifiers. The black and white monitors never gave any trouble, though. Of course in those days all this hardware came with shelves of ring binders full of schematics, maintenance instructions, and software descriptions. Other peripherals included XY magnetic tablets (before the days of computer mice) and pen-plotters for printing maps. When the PDP11/70's were retired, I took a screwdriver and dismantled the front panel of one of them, with all the address/data entry keys and register lights. A colleague took the panel from the second one. I still have it, nearly 25 years after the last program ran. When the PC revolution came and computing was no longer centralized, the job wasn't interesting anymore, so I transferred to a job working with automatic test equipment, and found myself with a Teradyne L210 tester and a few VAX stations. When I retired from the job, I think I was one of last people in the organisation who still worked with the VAX/VMS operating system.  

目前平板电视(包括LCD电视和PDP电视)同质化现象非常严重，由同质化而引发的恶性价格竞争导致平板电视的市场零售价每个月都以几百块人民币的 速度往下跌。而要有效止住这一价格下跌趋势，甚至逆势上扬，最容易想到的同时也许是最有效的产品差异化解决办法就是增加互联网TV功能，它几乎必然是平板 电视今后的唯一发展方向。理由有四：一是互联网上无穷无尽的音视频内容使消费者不必担心没东西可看；二是娱乐休闲时间日趋减少的消费者渴望“按需点播”的 消费模式，消费者不必再担心在有时间的时候看不到想看的内容；三是内容提供商很容易建立一种可操作的基于个人帐号的全新全民计费模式；四，平板电视一联上 互联网，那么它的应用‘潘多拉盒子’就打开了，从此平板电视产品的差异化程度和空间将只局限于系统设计制造商的想像力。 业内越来越多的有识之士开始认同这一发展趋势。例如，北京希图视鼎科技有限公司总裁刘锦湘博士表示：“互联网必定是平板电视的主流发展方向，完全没有必要借道PC上网或下载音视频节目。我认为数字媒体适配器是没有前途的。” 此外，尽管PC和PVR一直被业界热捧为未来数字家庭的信息和娱乐中心，但个人认为互联网TV可能更适合扮演这一角色。重要理由包括：1）未来的互 联网TV的屏幕足够大，今后完全可以用画中画技术来同时显式运行多种应用，如父亲可以在浏览互联网新闻，儿子在收发电子邮件，女儿在用互联网打国际可视电 话，母亲在欣赏互联网电视节目，祖父祖母则可以同时在观看CCTV的电视节目；2）TV一般摆放在全家人的交流中心场所，即客厅；3）互联网TV可为任何 消费者提供‘所见即所得’的直观友好用户界面，基本上任何人一看即会操作；4）现代遥控技术也日趋丰富和完善，如红外、Zigbee、蓝牙和MEMS加速 度计等，特别是后者，它将使得用户在空中挥挥手指就能控制互联网TV上的光标。 大屏幕互联网TV使得消费者有可能舒适地坐在沙发上完成以前需要TV、PC、笔记本电脑、DVD播放机、DVD录像机、手机、MP3播放机、PMP 和固定电话等多种电子设备才能实现的功能，如上网、收发邮件、播放音乐和电影、打国际语音或可视长途电话、收看和录制卫星/有线/地面和互联网电视节目、 监控家庭门禁和保安防盗系统、播放数码相机/摄像机和数码相框中的图片/图像等等。 随着目前大屏幕平板电视成为家庭消费的主流，未来的互联网TV需要具备在大尺寸屏幕上同时实时接收、处理和显示多种高清/标清音视频流的能力，这就 要求它必须采用处理性能非常强大的流媒体处理平台。此外，由于互联网上不断涌现采用新格式的音视频流内容，因此这一处理平台还必须是可编程的。由于互联网 TV针对的是对价格非常敏感的大众消费电子市场，因此它能否快速为市场所接受取决于市场上有没有满足其高性能要求的低成本、低功耗媒体处理器解决方案。 刘锦湘表示，现有的以ARM内核+通用DSP或专用硬件加速器为主的媒体处理器架构的性能已无法满足这一市场的特殊需求，因为ARM内核+专用 MPEG-4/H.26?等硬件加速器架构尽管同时具备高速度和低功耗优势，但该架构的缺点是缺乏灵活性，一旦互联网上出现新的音视频格式，这一架构就很 难进行升级支持，因此其目标应用市场只能是非常有限和确定的，如MPEG-4/H.26?视频监控系统或PMP。 ARM内核+通用DSP架构的典型代表是TI的DaVinci平台，它虽然具备了灵活性，但其缺点是性能还不够高，且功耗还较大。例 如，DaVinci目前还做不到实时(每秒30帧)完成D1分辨率H.26? Main Profile编码任务或D1分辨率MPEG-4 Main Profile编解码任务。为了解决这一问题，希图视鼎推出了下一代的媒体处理器架构，即RISC CPU+多个专用DSP(如向量DSP)，这一新架构不仅性能比DaVinci高，而且功耗也更低。希图视鼎声称，中国TV OEM仅需增加40美元左右的成本就可使它们的TV产品变成互联网TV。新兴公司Vivace也看到了这一紧迫的市场需求，并相应推出了采用类似架构的高 性能媒体处理器产品。 不过，上海杰得CEO欧阳合认为，对于屏幕不太大的便携式多媒体手持设备而言，只需支持主流音视频格式就够了，因为互联网上已经有足够的娱乐内容。 这类产品即便需要支持实时IPTV也不需要那么高的性能，而且消费者更看重的是功耗指标。新架构也许能提供更高的性能，但问题是你有没有足够的资源、时间 和一个强大的生态系统去为它开发操作系统、算法和应用程序。杭州微元科技市场总监张三毛也表示，从新一代多媒体设备开发商的角度来说，他们最关注的是上市 时间，因此他们通常只要求我们的方案支持主流的音视频协议。